Sciences : histoire orale

HAGENMULLER Paul, 2001-06-12

Sophie Jourdin — 2011-11-03T15:23:16Z

Paul Hagenmuller, born in Alsace in 1921, developed solid-state chemistry in France. He first initiated a research program at the University of Rennes (1956-60). In 1960 he set up a dynamic laboratory in Bordeaux. In 1964, Hagenmuller organized an international conference dedicated to the relations between structure and physical properties in oxides of the transition elements. The meeting gathered together chemists, crystallographers and solid-state physicists and prompted the establishment of an international community of solid-state chemists. In Bordeaux, Hagenmuller became the head of a research school working, at the interface between physics and chemistry, on the relation between atomic/electronic structure and physical properties, with a strong emphasis on industrial applications.

The Bordeaux research school has attracted scientists and students from all over the world (both developed and emerging countries) and many brilliant chemists of the next generation such as Jean Rouxel were trained in Bordeaux. Paul Hagenmuller retired in 1994. A jubilee celebration was organized at the Maison de la chimie in Paris in 1997. In 2001, his 80th birthday was celebrated in a special issue of the journal Solid State Chemistry.

HERVE ARRIBART (HA) : Pouvez vous retracer votre formation, vos débuts dans la carrière ?

PAUL HAGENMULLER (PH) : Depuis que je m'intéresse à la science je me suis préoccupé de la physique. Je me suis demandé pourquoi les matériaux avaient telle ou telle couleur, tel ou tel comportement électrique, magnétique, optique ... J'ai donc été porté vers la physique, plus tard vers la mécanique par extension, dès que j'ai entrepris mes études de science. Ces études ont eu lieu en 1940 à l'université de Strasbourg, repliée à Clermont Ferrand. Mon statut était celui d'un réfugié politique puisque j'avais quitté l'Alsace pour échapper au système politique allemand et parce que je me refusais d'être un jour mobilisé dans l'armée allemande. A Clermont, pour des raisons financières j'ai fait le choix de la chimie, séduit par la diversité des méthodes de préparation mais choqué parce que la chimie était alors très descriptive et n'était pas encore une science déductive, de réflexion.
Sur place, je suis entré en résistance, je faisais du sabotage. J'ai été arrêté en 1943 et envoyé en camp de concentration à Buchenwald. Là j'ai appris à me taire. J'ai travaillé sur les V2. J'ai appris le russe avec les prisonniers russes ; j'avais de bons contacts avec les communistes allemands. Puis j'ai été envoyé à Dora où c'était plus dur.
Après la guerre, André Chrétien m'a proposé un sujet de thèse sur la formation de nitrites complexes en solution aqueuse, puis une recherche sur la réduction de divers oxydes par des hydrures d'alcalino-terreux. J'ai accepté parce qu'il y avait un appareil mathématique. Puis au lendemain de ma thèse je me suis dit : il faut que je travaille sur des choses plus concrètes, les matériaux. J'ai voulu revenir à mes anciennes amours les matériaux. Je suis parti au Vietnam dans le cadre d'un accord avec la direction de l'enseignement supérieur et moi. Je partais pour deux ans 1954-56, au moment où la France se désengageait et voulait garder des relations culturelles. Au retour il était entendu que je pourrai choisir un poste de maître de conférences parmi ceux qui étaient disponibles en chimie. Ces deux ans de Vietnam ont été pour moi une période de décantation, de réflexion. Et quand je suis revenu j'ai voulu, d'une part, me préoccuper de physique ce qui suppose la détermination des structures atomiques - pour comprendre les propriétés physiques il faut savoir quelles sont les positions des atomes - et, d'autre part, il faut une certaine habileté à préparer des matériaux par des techniques nouvelles fort différentes.

HA : Quelles étaient alors les relations entre physique des solides et chimie des matériaux en France ?

PH : Aujourd'hui la physique s'est beaucoup rapprochée de la chimie parce que, de part et d'autre, on a compris que c'était indispensable pour faire des matériaux à propriétés spécifiques intéressantes sur le plan de la science fondamentale et intéressantes aussi sur le plan des applications. Au début des années 60, on en était à se chercher. Moi, j'avais fait un choix très clair : faire une chimie orientée vers la physique, plus tard vers la mécanique. Maintenant c'est devenu presque de routine, ne serait-ce que par ce que les chimistes pour bien connaître leurs matériaux sont obligés d'utiliser des méthodes de caractérisation physiques. La physique s'est imposée dans les perspectives de la recherche comme par les nécessités quotidiennes : savoir où sont les atomes et les électrons.
Donc au retour du Vietnam mon objectif était d'associer la physique et la chimie. J'ai eu la chance que dans mon poste à Rennes il y avait quantité d'excellents étudiants, mais en chimie personne ne voulait faire de la recherche sous prétexte qu'il n'y avait pas de moyens. J'ai décidé que j'allais lancer des thèses dans ce domaine à l'interface de la physique et de la chimie. On a d'abord tâtonné. On a travaillé sur le bore, sur les hydrures. Parmi les études réalisées à Rennes se trouvait la réduction d'oxydes par l'hydrure de lithium. On était intéressé par les hydrures de bore et d'aluminium qui comportaient des liaisons dites pont-hydrogène originales. Ceci m'a donc amené à réduire le V2O5 par l'hydrure de lithium et nous avons constaté qu'il y avait des phases intermédiaires qui devaient être les futurs bronzes de vanadium et de lithium, qu'on a appelées plus tard b et g. La phase a étant la solution solide de lithium dans V2O5. Alors j'ai pensé que ces matériaux étaient intéressants : s'il y a là un domaine d'existence, les propriétés physiques doivent varier à l'intérieur de ce domaine et si, par chance, ce domaine est suffisamment grand on peut faire ce qui est plus difficile dans les solutions solides limitées, de type oxydes non stœchiométriques. On s'est préoccupé de manière systématique des bronzes de vanadium qu'on a préparés par voie synthétique. Dans les années qui ont suivi - de 1960 à 70, j'étais alors à Bordeaux où un grand nombre de chercheurs de Rennes m'avaient suivi - on a préparé un grand nombre de phases de bronzes de vanadium par analogie avec les bronzes de tungstène qui avaient déjà été signalés. On a fait systématiquement des études magnétiques et électriques pour caractériser le mode de conductivité. Il est apparu que lorsqu'on insérait le lithium dans le réseau, on remplissait les états électroniques du vanadium, qui forment la bande de conduction. Les électrons devenaient donc de plus en plus délocalisés au fur et à mesure que leur nombre augmentait et on passait d'un état semi-conducteur à l'état métallique.

BERNADETTE BENSAUDE-VINCENT (BBV) : Quelles étaient vos relations avec le groupe de Robert Collongues ?

PH : Collongues avait été élève de Georges Chaudron, comme André Michel, Paul Lacombe, Jacques Bénard. J'avais d'excellentes relations avec Collongues. Nos domaines se recouvraient partiellement sur la non-stœchiométrie mais on avait des approches différentes. Lui enlevait des ions, nous on faisait de la chimie d'insertion. Collongues aimait bien se singulariser par rapport à moi mais dans la pratique nous avions la même politique sur des matériaux différents. Il y avait chez lui le même désir de systématique et de réflexion en profondeur. Collongues considérait que la bonne expérience était importante mais qu'elle devait illustrer une réflexion de fond. Il pensait que la science était avant tout la réflexion intellectuelle.
J'ai fait de la chimie sous pression à la manière d'un tailleur : choisir une structure cristallographique, écrire la formule d'une composition chimique, puis la stabiliser dans un degré d'oxydation élevé. Après avoir discuté la structure puis la formule, on préparait sous haute pression. C'était du design pour la conductivité électronique, les propriétés magnétiques, ou les propriétés magnéto-optiques et plus tard également pour la conductivité ionique.
Nous nous intéressions systématiquement à l'évolution de toute propriété physique originale en fonction de la composition et de la structure. Un nœud important dans cette évolution fut le colloque organisé à Bordeaux en 1964 sur les oxydes d'éléments de transition.

HA : Quelle fut la portée de ce colloque de 1964 ?

PH : Ce fut le moment où s'est constituée une communauté internationale de chimie du solide. Le colloque a rassemblé les chimistes qui nous étaient familiers, des cristallographes (Erwin-Felix Bertaut, Charles Guillaud), des physiciens (Jacques Friedel). Parmi les étrangers Mike Sienko, John Goodenough du Lincoln Laboratory au MIT qui est venu pour la première fois à Bordeaux ; des Allemands : Wilhelm Klemm, Rudolf Hoppe, Harold Schäfer ; des Hollandais, des Belges, etc. Il est apparu qu'une conjugaison des méthodes de mesure physique, des méthodes de détermination structurale et une certaine flexibilité pour les changements de composition, pouvaient permettre d'optimiser un certain nombre de propriétés physiques. D'abord le magnétisme, ensuite il y a eu la ferro-électricité - comment accroître la distortion ferro-électrique et par voie de conséquence la polarisation ; enfin, la conductivité ionique, d'abord dans des matériaux isolants au point de vue électronique et ensuite dans des matériaux dits cathodiques utilisables dans des batteries parce que conducteurs mixtes.
Je dois dire que ce qui fut déterminant pour l'avenir de la chimie du solide ce fut la venue de John Goodenough à ce congrès parce qu'il a popularisé parmi nous l'idée de l'importance de la liaison chimique. On a compris qu'on pouvait renforcer ou atténuer la liaison chimique en modifiant la composition, en particulier en jouant sur la liaison antagoniste. Par exemple si on compare le zirconate de baryum avec le titanate de baryum, la liaison baryum-oxygène est renforcée dans le zirconate par rapport au titanate. Inversement si on remplace dans le titanate de baryum, le baryum par le strontium comme la liaison strontium -oxygène est plus forte que la liaison baryum-oxygène, la liaison titane-oxygène est affaiblie, ce qui peut amener une variation très forte de la polarisation en fonction de la température, juste en dessous de la température de Curie. Et on peut avoir ainsi des matériaux aux propriétés intéressantes.

HA : Le rapprochement de la physique et de la chimie avec une orientation vers les applications constituerait-il donc l'identité de la chimie du solide à cette époque ?

PH : Oui nous avions un besoin civique de justifier les crédits que nous demandions par une application dans la vie économique. De plus, le travail avec des industriels fait naître des problèmes inattendus qui sont des challenges et qui sont nourrissants.
Une deuxième date importante dans l'institutionnalisation de la chimie du solide est 1978. Sur mon initiative la Société française de Chimie a créé en 1976 une division de chimie du solide, dont j'ai naturellement été le président. J'ai organisé la même année un premier colloque national de chimie du solide à Nantes. Sur ma proposition et sous ma présidence s'est tenu à Strasbourg en 1978 le premier congrès européen de chimie du solide, organisé par Jean-Claude Bernier (Strasbourg a été choisi pour une raison stratégique,). L'intervalle entre deux congrès consécutifs est maintenant de 3 ans ; le huitième congrès européen a lieu en juillet 2001 à Oslo.

HA : Quel était l'état des relations entre science et industrie en France à cette époque ?

PH : Il y avait une tradition de collaboration en métallurgie et en chimie : Chaudron et ses élèves, Lacombe, Bénard étaient très impliqués. Robert Collongues l'était aussi dans le domaine des monocristaux. Mais il y avait une forte hostilité syndicale au nom des grands principes : il ne faut pas mettre la science au service des grands intérêts privés. Les choses se sont atténuées à la veille de l'élection présidentielle de 1981. J'ai eu la visite de M. Kahane, longtemps doyen à Orsay, qui s'était rallié à la collaboration avec l'industrie privée. Cela a facilité cette évolution qui, de ma part, ne rencontrait aucune résistance car j'étais un scientifique et je n'avais pas à me poser des problèmes de déontologie qui me paraissaient un peu artificiels. Mais une partie de mon entourage était réticente à travailler avec l'industrie.

HA : Est-ce la crise pétrolière de 1973 qui a contribué à anoblir le rapprochement entre science et industrie ?

PH : Oui. Du fait de notre préoccupation entre propriétés physique et composition, nous avons été conduits à travailler sur des composés non-stœchiométriques d'intercalation et nous avons constaté après 1973 qu'il y avait possibilité d'intercalation ou désintercalation à basse température grâce à l'électrochimie comme on le faisait aux Etats Unis. Exxon et Bell étaient plus concernés que nous par la crise de l'énergie.
Les recherches sur la conductivité ionique ont été encouragées par la crise de l'énergie. Après la zircone déjà exploitée par Nernst, puis étudiée par la NASA et par Collongues ; il y avait eu AgI. Puis il y a eu l'alumine-b qui a suscité de nombreux travaux. CGE a dépensé beaucoup d'argent. L'alumine-b est un matériau très particulier. J'étais très sceptique. On a abaissé la température de fonctionnement, mais c'est encore trop haut pour un véhicule électrique. Et puis le soufre attaque la membrane. Finalement on a renoncé, pensant qu'avec des batteries au lithium on irait plus loin. Les derniers efforts de développement visaient plutôt le stockage d'énergie en période creuse. Les nasicons eux ne sont pas attaqués et ils présentent un avantage au plan fondamental car leur structure est plus simple. Ils ont de bonnes performances, qu'on pouvait maîtriser avec une juste proportion de sodium.

HA : Pouvez vous évoquer vos travaux sur la conduction ionique ?

PH : Avant 1973, on a publié un grand nombre de documents sur des conducteurs ioniques. On s'inspirait comme modèle de réflexion des bronzes de tungstène bien que la plupart des travaux publiés à l'époque fussent des études structurales et que les bronzes de tungstène soient métalliques. On avait également préparé une série de nouveaux bronzes de tungstène. Ce travail s'est étendu à des bronzes oxyfluorés, à des bronzes de vanadium et de molybdène contenant les deux cations vanadium et molybdène plus le sodium et le lithium. Puis au début des années 1970, on s'est attaqué aux premiers bronzes de manganèse NaxMnO2 et puis aux bronzes de cobalt KxCoO2.
Sur ces entrefaites il y a eu la grande crise pétrolière de 1973. Les pays occidentaux ont eu peur de manquer d'énergie et donc on s'est occupé de sources d'énergie non fossile et de stockage d'énergie. Un certain nombre de gens ont voulu faire des batteries. Exxon et la Bell Telephon, Whittingham et Murphy en particulier, ont travaillé sur ces matériaux non plus comme nous l'avions fait vers 500°C avec des phases en équilibre thermodynamique mais à basse température par intercalation ou désintercalation électrochimique.
Une spécialité à Bordeaux c'était les fluorures conducteurs. On remplaçait systématiquement l'oxygène par du fluor parce qu'il a la même taille et présente une liaison plus faible. On pouvait ainsi atténuer les interactions magnétiques. Comme pour la zircone, on dope les fluorures systématiquement. Watanabe avait déjà préparé les premières batteries au fluor.
Jean Rouxel s'était intéressé à l'époque où il était mon élève aux sulfures, aux sulfures à couche en particulier. Entre les couches de FeOCl et FeSCl par exemple, on pouvait intercaler beaucoup de choses, comme l'ammoniac ou les amines. Jean Rouxel a préparé NaxTiS2, un matériau qui avait été préparé par Rudorf à Fribourg, qui le considérait comme une curiosité. Mais Rouxel a très vite réalisé qu'il devait y avoir un domaine d'existence. Or il s'est avéré que Li xTiS2 avait un large domaine d'existence. Jean Rouxel a poussé dans cette voie et il a étudié un grand nombre de sulfures et sélénures à feuillets alors que nous nous intéressions plutôt aux oxydes. Il y avait une sorte d'accord empirique entre nous : Nantes les sulfures, Bordeaux, les oxydes. Nous avons étudié des matériaux sur le plan de la synthèse, dans des conditions d'équilibre thermodynamique plus que par intercalation désintercalation.
Il y a une grande variété de méthodes topologiques ou non de relative basse-température qui permettent d'obtenir des matériaux nouveaux. Mettre un mélange très fin de poudres sous hautes pression pour que se déclenche une réaction brutale qui prend fin lorsque l'un des deux constituants initiaux a disparu. Donc c'est un échauffement brutal suivi d'une trempe. Ce qui permet d'obtenir des borures ou des silicium stables seulement à haute température.
Beaucoup de ces matériaux sont métastables mais on peut les utiliser dans des dispositifs.
Jean Rouxel a apporté beaucoup dans le domaine des réactions d'intercalation-désintercalation. Les oxydes lorsqu'on les désintercale perdent des électrons cationiques. C'est une oxydation cationique. Lorsqu'on part de LixCoO2 vers CoO2 on perd des Li+, mais on perd également des électrons qui proviennent des niveaux d. Mais pour les séléniures, ce sont les niveaux anioniques qui sont les plus élevés. Et lorsqu'on oxyde, c'est l'anion qu'on oxyde. On passe de Se2- à Se- et de Se- à Se pour des raisons de stabilité de liaison. Et Jean Rouxel a montré qu'il y avait une évolution graduelle pour les éléments 3d à l'état de sulfure entre TiS2, qui a une structure à couches, et CuS2 qui a une structure avec un ion S de type pyrite. Il a fait une analyse précise dans les cas douteux où les niveaux cationiques et anioniques sont à peu près de même énergie. L'analyse très fine des distances inter-atomiques lui a montré si c'était le cation ou l'anion qui était oxydé. Il a également fait beaucoup de choses sur les bidimensionnels qui sont ici hors sujet.

HA : Qu'est-ce qui a manqué en France alors que les compétences étaient là pour donner l'impulsion sur les batteries au Lithium ?

PH : Il y a un très grand nombre de batteries réversibles au lithium pour des applications diverses depuis les montres jusqu'aux batteries de taille moyenne utilisées par les militaires pour observation spatiale avant bombardement. Mais le marché important, c'est le véhicule électrique, non polluant. Du moins en partie car on s'est résigné au véhicule hybride. Le véritable marché ce serait la voiture électrique -éventuellement hybride- ce qui suppose des batteries de grande taille. Probablement l'électrolyte sera un polymère PEO imprégné d'un sel de lithium avec un gros anion, type matériau Armand. La cathode sera probablement riche en cobalt ce sera un matériau voisin de LixCoO2, plutôt un oxyde qu'un sulfure parce que la tension est plus élevée. Mais pour l'anode ce n'est pas encore évident. Si on pouvait faire mieux que les composés d'intercalation du lithium on serait content. Mais actuellement il n'y a pas encore de solution. Il y a donc premièrement un problème de matériau qui freine cette évolution. Deuxièmement il y a un problème de prix. Ajoutez à cela qu'une batterie au lithium doit être scellée car le lithium est sensible à l'atmosphère et vous voyez que ce n'est pas évident. Une solution concurrente est la batterie hydrogène consistant à stocker l'hydrogène dans un alliage métallique et puis à libérer l'hydrogène. Ce modèle permet des puissances plus élevées que la batterie au lithium mais là aussi il y a un problème de vieillissement car après un certain nombre de cycles, l'alliage s'oxyde car l'oxyde est plus stable que l'hydrure. Ce problème n'est pas encore résolu avec un coût acceptable pour l'utilisateur. A cet égard, il y a une coupure entre le scientifique et l'utilisateur.

HA : Concernant les relations entre physique et chimie qu'est-ce qui a favorisé le rapprochement ?

PH : Les physiciens ont fait des efforts pour parler un langage plus proche de celui des chimistes. J'ai parlé déjà de John Goodenough. Nevil Mott aussi était un homme qui s'exprimait dans un langage compréhensible pour un chimiste. Par exemple, lorsqu'il a obtenu des transitions isolantes par changement de composition au sein d'un domaine d'existence, on comprenait ses préoccupations et il comprenait les nôtres bien qu'on raisonne sur des modèles un peu différents. On est ainsi arrivé à préparer dans des bronzes de tungstène oxyfluorés des matériaux qui sans changement de structure manifestaient une transition métal-isolant. Les physiciens ont fait des progrès. L'équipe de Friedel était très préoccupée de parler un langage qui nous était commun. Je pense à Denis Jérôme, Claude Berthier à Grenoble.

HA : Le travail de physiciens sur la caractérisation très fine vous a-t-il aidé ?

PH : Je me souviens de discussions à Orsay sur les hexaborures. Les physiciens voulaient des matériaux qu'on appelait thermo-ioniques - mais c'est un mot malheureux : on devrait plutôt dire thermo-électronique - c'est à dire ayant un faible potentiel d'ionisation et susceptibles de cracher un jet d'électrons relativement puissant sous tension faible. On en a fait une étude systématique et on a essayé de préparer des cristaux.

HA : Et quel était l'enjeu ?

PH : L'enjeu était d'avoir ponctuellement un faisceau d'électrons puissant, par exemple pour des soudures, des soudures localisées. Outre la collaboration avec les physiciens d'Orsay on a aussi collaboré avec ceux de Grenoble. Plus que ceux d'Orsay, les physiciens de Grenoble avaient un langage très compréhensible. Il y avait un grand homme à Grenoble, Louis Néel. Il avait publié son travail sur le ferrimagnétisme en s'appuyant sur des modèles structuraux très clairs. La répartition des cations entre les sites tétraédriques et les sites octaédriques de la structure spinelle. Donc on comprenait pourquoi on avait des interactions d'abord anti-ferromagnétiques - ce qui constitue la base du ferrimagnétisme - entre des sites tétraédriques A et des sites octaédriques B, et pourquoi l'aimantation résultante était accrue lorsque le réseau prévalent contenait des cations avec beaucoup d'électrons d célibataires. Tous ces travaux - encouragés par les recherches militaires - ont permis une collaboration très fructueuse avec Grenoble. Je pense à Bertaut en particulier. Nous avons été encouragés, par exemple, à faire des études basse-température par Pauthenay qui nous a dit : c'est aux basses- températures qu'on détecte les phénomènes peu énergétiques.
Alors c'est l'époque où nous avons manqué le prix Nobel - Je dis cela en plaisantant, bien sûr !-. Nous avons préparé les premiers oxydes purs de Cu3+ : par exemple SrLaCuO4. Nous avions une telle habitude des solutions solides qu'on pouvait imaginer de préparer une solution solide avec La2CuO4 contenant du Cu2+. Mais pour nous, les solutions solides, c'était du travail secondaire. On cherchait à préparer des oxydes purs. Si on avait été préoccupé des solutions solides on aurait pu trouver des oxydes contenant à la fois du cuivre Cu 2+ et 3++. Comme par routine on caractérisait tous nos matériaux jusqu'à la température de l'hélium liquide, on aurait trouvé la supraconductivité. On ne l'a pas fait parce qu'on voulait des phases pures et non pas des solutions solides.
Bernard Raveau l'a fait avant Alex Müller. Il avait un objectif : comprendre ce qui se passait au point de vue des corrélations. Passer d'un semi-conducteur à un métal. Müller était un très grand physicien. Il a été surpris aussi mais il a tout de suite expliqué. Raveau a fait ses solutions solides. C'est même moi qui ai transmis sa publication au M[aterials] R[esearch] B[ulletin] mais j'ai regretté à l'époque qu'il n'ait pas fait de mesure à l'hélium liquide.

HA : Après avoir évoqué vos collaborations en France, pourriez vous parler de vos liens avec l'étranger ? Vous avez été précurseur pour les relations scientifiques avec les pays en voie de développement comme la Chine, le Maroc et l'Inde. Quelles étaient vos motivations ? Comment voyez-vous la science des matériaux dans ces pays ?

PH : J'ai toujours été persuadé que la science devait être internationale. Cela me distingue de beaucoup de mes compatriotes. Je suis toujours étonné que l'on fasse des quêtes pour aider la recherche en France sur le SIDA. Toute la recherche sur le SIDA, toute recherche de pointe est internationale et ce n'est pas parce que la France dépensera un peu plus d'argent que nécessairement, il y aura des progrès significatifs. La science doit être internationale.
J'ai donc eu des liens d'abord avec les pays développés car dans ce type de relation on se fait connaître mais aussi on apprend. Je suis allé souvent aux Etats Unis, moins par enthousiasme culturel, que parce qu'on y rencontre des gens de qualité. J'ai rencontré Goodenough, Al Cotton... j'ai rencontré à Berkeley ou à Stanford des gens de grande qualité. J'ai eu des relations suivies pendant un temps avec la Grande Bretagne mais les Anglais ont un sentiment de quant à soi. J'espère qu'avec le temps la Grande Bretagne va évoluer vers une intégration dans l'Europe. Les Allemands sont très favorables à cette intégration. Dès 1961 j'avais pris l'initiative d'emmener tout mon laboratoire en Allemagne pour un voyage de 15 jours. On est allé à Stuttgart, Karlsruhe, Heidelberg, Darmstadt, Giessen, Göttingen etc.. On a été très bien reçu par Wilhelm Klemm avec qui j'ai toujours entretenu d'excellentes relations. Mais ses élèves étaient jaloux. Les Allemands se sont sentis bousculés parce qu'un peu jaloux de gens qui faisaient beaucoup de bruit. Ils avaient une bonne tradition de chimie préparative, en relation avec l'industrie. Les Allemands ont compris que pour faire des matériaux nouveaux il fallait des techniques nouvelles comme la haute pression. Mais leur but c'était la performance tandis que le nôtre c'était de stabiliser des structures électroniques peu usuelles, grâce à la synthèse. Les Allemands se sont senti un peu gênés. Les gens leur disaient : vous utilisez des équipements de haute pression mais ce que vous faites c'est de la botanique alors qu'il faudrait réfléchir. Le but d'un équipement est de faire des matériaux à façon pour répondre à des problèmes déterminés. Les collègues allemands avaient un autre point de vue et je regrette qu'il n'y ait pas eu davantage de liens.
En revanche, toujours parmi les pays développés, j'ai eu beaucoup de liens avec l'Europe de l'Est. Pour deux raisons. D'abord, il y avait des gens de qualité chez les Soviétiques, les Polonais et les Tchèques. De plus j'étais un peu agacé de cette Europe coupée en deux du fait de la guerre froide. Donc je trouvais raisonnable qu'il y ait une présence de la France là où c'était relativement facile, c'est à dire la science. C'était intéressant pour eux et pour nous car nous avons eu de ces pays des personnes remarquables. J'ai eu des relations systématiques avec des laboratoires à Prague, Cracovie, à Moscou, à Kiev, Novosibirsk, à Sofia. Avec la Roumanie, c'était impossible car Madame Ceaucescu interdisait aux scientifiques de discuter avec des étrangers.
Avec les pays en voie de développement, la situation change d'un pays à l'autre. J'ai eu des relations avec le Maroc parce que l'université de Bordeaux et l'université de Rabat avaient des liens traditionnels. Je suis allé y faire cours. Il y avait de très bons étudiants je les ai encouragés à faire une thèse. Le nombre a crû considérablement. 30 ou 35 Marocains ont fait des thèses avec moi. J'avais une politique de sélection impitoyable ; je prenais les meilleurs et je les surpayais. Je voulais qu'ils n'aient pas de souci matériel pendant leur thèse. J'ai eu des liens plus occasionnels avec la République du Congo et quelques Tunisiens mais ils préféraient Marseille.
Avec la Chine j'ai fait un choix politique. J'ai compris que la Chine était un potentiel économique et humain. La France devait être présente à un moment où la Chine était exclusivement tournée vers les Etats-Unis. Je suis allé souvent en Chine. J'ai fait venir des étudiants chinois en les choisissant bien sûr excellents. Mes espoirs ont été dépassés par le succès car ils ne sont pas retournés en Chine mais partis au Canada ou aux Etats-Unis comme professeurs ou dans l'industrie. Ils se sont bien débrouillés. Maintenant c'est différent ; une majorité d'étudiants chinois reviennent en Chine.
L'Inde est aussi un pays avec lequel j'ai eu des relations. C'est une société où le savoir est respecté, une science de caste malgré l'abolition officielle des castes. Thaïlande, Malaisie, Indonésie...j'ai privilégié les pays asiatiques par rapport aux pays africains car la culture asiatique favorise la réflexion métaphysique et par conséquent scientifique. Néanmoins j'ai eu aussi des collaborations avec le Brésil, le Chili et l'Argentine. Le but étant d'aider ces pays dans leur développement industriel. Je suis d'ailleurs membre de l'Académie des sciences brésilienne depuis 1988.
Vis à vis des étudiants du tiers monde, j'ai toujours considéré comme ma responsabilité de leur donner une thèse originale et non pas, comme on le fait souvent, de leur faire remplir des vides dans le laboratoire ou de servir de main d'œuvre. Les étudiants du tiers monde que l'on fait venir en Europe il faut bien les choisir et bien les former pour qu'ils deviennent des maîtres.

HA : Je serai curieux de connaître votre point de vue sur l'évolution de la chimie des matériaux et le rapprochement avec la biologie.

PH : Je ne me sens pas compétent dans l'interface chimie/biologie. Mais mon expérience à l'interface physique et chimie me rend plutôt sympathique cette perspective d'une ouverture de la chimie vers la biologie. Elle est défendue par Pierre Pottier, Guy Ourisson, Corriu.
Sur l'interface physique/chimie, cela s'est moins bien passé. Peut-être que je n'ai pas su convaincre. Quand on prêche, on se fait des adeptes mais aussi des ennemis. Cela est vrai au CNRS. Celui qui prêche secoue les caciques, les gens en place. Quelqu'un comme Fernand Gallais était fermement hostile à mon projet d'interface avec la physique. Par contre j'ai rencontré beaucoup de sympathies du côté de Pottier, de Jacques Livage.
Pour revenir aux oxydes supraconducteurs, il s'agit d'un cas intéressant de collaboration entre physiciens et chimistes. Très vite, j'ai compris que l'on avait plafonné et puis à un moment donné il était clair que Tc était d'autant plus élevé que la bande de conduction était plus étroite. Et plus la bande de conduction est étroite plus le matériau est instable et a tendance à se dismuter en donnant un mélange de deux phases. J'ai compris cela très vite mais beaucoup ne l'ont pas compris. Il y a donc eu un emballement. Il a rapproché les chimistes des physiciens. Il est dommage que personne n'ait proposé un modèle simple permettant aux chimistes d'innover de manière simple comme on avait innové dans le domaine de la conductivité ionique, du magnétisme, de la ferroélectricité, des magnéto-optiques ... ou même des composites thermo-structuraux. Il a manqué quelqu'un qui propose un modèle intuitif liant les propriétés à la liaison chimique. Goodenough aurait pu le faire mais il était trop vieux, trop pressé de publier des matériaux miracles. Les matériaux miracles sont difficiles à reproduire. Celui qui essaie il n'a pas le même four ... Ces matériaux sont métastables, ils ne sont jamais parfaitement purs. Ils n'ont jamais le même nombre de lacunes d'oxygène. Donc ce n'est jamais parfaitement répétitif. Cela exclut toute réplication sérieuse parce qu'un matériau n'est utilisable industriellement que s'il est relativement simple à préparer et à utiliser. Telle est la raison de l'échec de la diode Josephson sur laquelle IBM a dépensé beaucoup d'argent. A l'époque j'étais d'ailleurs conseiller d'IBM.

BBV : Est-ce qu'il y a eu des matériaux sortis de vote laboratoire qui ont été industrialisés ?

PH : Il y a d'abord eu les varistors. J'ai fait beaucoup avec la Thomson CSF dans ce domaine. Il y a eu LixCoO2 et puis il y a les céramiques composites de R. Naslain : fibres de carbone infiltrées par SiC qui permet de travailler à des hautes températures pour les matériaux de rentrée de la fusée ou du satellite dans l'atmosphère. Car lorsque l'engin revient dans l'atmosphère, il y a un risque d'oxydation. L'astuce consistait à infiltrer - non pas déposer en surface - SiC à partir d'une phase vapeur. Alors à l'air SiC s'oxyde en donnant SiO2 qui s'infiltre dans le matériau à base de carbone et permet de le prolonger.

BBV : Pourriez vous préciser quelles étaient vos relations avec l'industrie et comment elles ont évolué ?

PH : J'ai toujours eu des relations avec l'industrie. Quand j'étais à Rennes j'ai été contacté par Raymond Paul, un des responsables de la recherche à Rhône Poulenc et il m'a vivement encouragé à travailler avec Rhône Poulenc. J'ai eu plusieurs bourses de thèses payées par l'industrie - parfois il fallait publier des résultats plus tard. Rhône Poulenc a payé la thèse de Michel Pouchard sur les bronzes de vanadium au début des années 60. Ensuite il m'a paru tout naturel de travailler avec l'industrie. J'ai travaillé avec Saint-Gobain sur les verres, en particulier sur les verres conducteurs du lithium et du sodium avec Levasseur, sur les verres sulfurés à base de B2S3. Les verres sont un matériau merveilleux. Ils ont une composition qui est flexible. Vous tombez un peu à côté, cela n'a pas d'importance les propriétés ne sont guère modifiées. Vous n'avez pas le problème des matériaux cristallins où, par suite de la moindre erreur, de la moindre difficulté de préparation, une deuxième phase d'impuretés se forme à côté. Là il vous reste une phase. D'autant plus qu'on peut préparer les verres par trempe brutale donc énormément de matériaux sont vitreux alors qu'il y a 30 ou 40 ans c'était différent.
J'ai eu beaucoup de liens avec l'industrie locale : Aérospatiale et SNECMA, avec SNPA (société nationale des pétroles d'aquitaine : ancêtre d'Elf) sur comment purifier le gaz de Lacq...Ma porte était toujours ouverte, on élargissait le champ de nos recherches à la demande car l'industrie n'est pas un boulet.

BBV : Est-ce que ces liens étaient encouragés par le CNRS ?

PH : Le CNRS était informé bien sûr. Et puis quand on est devenu un laboratoire propre en 1966 Curien était très favorable aux relations avec l'industrie. On a un des contrats avec Saint-Gobain, avec Rhône Poulenc devenu Rhodia, avec Ugine Kuhlman devenu Péchiney. Nous avons même eu des liens avec General Electric aux USA pour les borures, avec BASF sur le di-oxyde de chrome pour les bandes d'enregistrement.

BBV : Quelles sont les méthodes et techniques utilisées dans votre laboratoire ? Et comment ont-elles évolué au cours de votre carrière ?

PH : Au début le B-A-BA c'était la diffraction X. Puis pour bien comprendre la structure on a eu un équipement pour des monocristaux. On a préparé des mono-cristaux pour déterminer les structures. Maintenant on a fait de gros progrès et on peut sur des spectres de poudres lorsque la poudre est de bonne qualité déterminer la structure par les méthodes Riedveld en faisant des hypothèses simples sur la structure la plus probable. La diffraction X a été fondamentale et a débouché ensuite sur la microscopie électronique en transmission qui permet de voir les défauts locaux. C'est merveilleux. La diffraction X était une méthode à grande distance. Par contre la microscopie électronique en transmission vous donne les défauts localisés et étendus. C'est une préoccupation que j'ai eu beaucoup à propos de non-stœchiométrie. Quand on passe d'une phase perovskite ABO3 à une phase brownmillérite A2B2O5, on perd de l'oxygène. Alors à haute température les lacunes d'oxygène sont désordonnées. A température plus basse, elles s'ordonnent en fonction du cation B. Quand c'est du fer ou du gallium, un cation isotrope, on a soit des tétraèdres parce qu'il y a pas de lacune, soit des octaèdres car les lacunes marchent par deux. Donc dans une structure brownmillérite on a une séquence octaèdre,-tétraèdre, octaèdre-tétraèdre, et dans la structure perovskite c'est octaèdre-octaèdre-octaèdre. Alors on peut trouver à condition de faire des recuits à température assez basse - quelques centaines de degrés - des phases intermédiaires avec 2 couches octaèdres, 1 couche tétraèdre, 3 couches octaèdres, 1 couche tétraèdre. Et bien sûr quand on chauffe le désordre s'installe à cause de l'entropie d'empilement. On a étudié de manière systématique comment on passe de défauts isolés aux défauts ordonnés, étendus. Et cela a des conséquences au point de vue de la conductivité de l'ion oxygène. Parce que maintenant on a de nouvelles préoccupations. On veut par exemple extraire l'oxygène de l'air par des membranes de perovskite lacunaire ou détruire les traces de CO en oxydant par l'eau. Dans ce cas, vous avez CO2 - qui est quand même moins toxique que CO, sauf sur le plan idéologique - et vous avez de l'hydrogène. On utilise des perovskites lacunaires qui doivent être conducteurs de l'oxygène - ce qui est normal - mais aussi conducteurs électroniques car le transfert se fait sous tension donc il faut que les ions O2- migrent à travers les lacunes de la structure. Il y a donc un aspect pratique pour les capteurs d'oxygène, la purification des gaz. Les Norvégiens utilisent ces méthodes massivement pour transformer le gaz de la Mer du Nord en un gaz exempt de CO. Norsk-Hydro dépense des sommes considérables pour cela. J'ai été invité pour parler avec les gens impliqués par ces recherches.
Donc pour résumer : nos efforts se sont situés à l'interface entre physique et chimie et se concentraient sur l'étude des relations entre composition, structure et propriétés avec la perspective d'applications industrielles.

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Pour citer l'entretien :

« Entretien avec Paul Hagenmuller », par Bernadette Bensaude-Vincent et Hervé Arribart, 12 juin 2001 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article124.
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Entretien avec Paul Hagenmuller, par Bernadette Bensaude-Vincent et Hervé Arribart, 12 juin 2001

Lieu : Paris, France

Support : enregistrement sur cassette

Transcription : Bernadette Bensaude-Vincent et Hervé Arribart

Edition en ligne : Sophie Jourdin

GRIESEMANN Jean-Claude, 2001-02-24

Sophie Jourdin — 2011-10-28T14:24:36Z

Jean-Claude Griesemann was trained as a physicist. He has a PhD in plasma physics and joined Renault initially as a specialist on lasers in industrial processing. From 1991 to 1998 he has headed a unit on the fuel cell for vehicles within Research Management (Direction de la Recherche) at Renault.

BERNADETTE BENSAUDE-VINCENT (BBV) : Quelle est votre opinion sur le véhicule électrique ?

JEAN-CLAUDE GRIESEMANN (JCG) : Le véhicule électrique est un concept idéal qui porte dans ses gènes les limites qui définissent son créneau d'application. L'énergie avec une batterie lithium vise à une autonomie maximale de 180-200 Km, avec 4 heures de recharge. Le coût élevé de cette technologie n'a pas encore permis aux constructeurs de dégager une rentabilité vraisemblable. La voie ouverte par Toyota, objet de développements en cours, c'est l'hybride : moteur thermique avec assistance électrique légère pour adoucir les transitions. C'est l'optimum du raffinement électrique sur un véhicule conventionnel.

BBV : Y-a-t-il plus d'espoir du côté des piles à combustibles ?

JCG : Le concept existe depuis Grove (1827) mais les piles à combustibles ne sont entrées en application que dans la seconde moitié du XXe siècle dans les capsules Gemini. C'était très bien adapté. L'hydrogène existe dans le propulseur, l'oxygène existe en tant que comburant des propulseurs ; la pile à combustible utilise ces réactifs pour fournir du courant par migration des ions H+ à travers l'électrolyte et produit de l'eau qui est grandement nécessaire dans une station habitée. L'utilisation d'oxygène pur affranchissait l'électrolyte alcalin du risque de contamination par le dioxyde de carbone.

BBV : Est-il possible de transférer la technique aux automobiles ?

JCG : L'air ambiant contient du CO2. On a utilisé la chaux sodée pour capturer le CO2 : La société ELENCO en Belgique, soutenue par le Centre d'études nucléaires de Mol a construit un autobus utilisant une batterie de ces piles à combustible alcalines : il comprenait une remorque contenant la pile et la chaux sodée. La faillite de la société ELENCO n'a pas permis la venue à terme de ce premier démonstrateur.
En France, un grand programme-cadre de recherche et développement pour l'industrie des transports terrestres (PREDITT) a été lancé en 1991 par le gouvernement français, favorisant un partenariat entre Renault, PSA, le CEA, le CNRS et l'Agence pour l'environnement et la maîtrise de l'énergie (ADEME). Ce programme sur 5 ans fut doté d'un budget de 50 million de FF : 25 millions apportés par l'ADEME et le reste par les partenaires industriels. Gérard Chaumain alors responsable des technologies avancées à l'ADEME (22 Rue Louis Vicat, Paris 15e) a joué un rôle moteur dans ce projet.
Le programme de recherche a été articulé autour de trois questions :

- qu'est une pile à combustible ?
- comment construire une pile à combustible ?
- comment la fabriquer dans des conditions économiques réalistes ?
Le programme de recherche a mobilisé le CEA, 12 laboratoires du CNRS et un institut de recherche privé, sous contrat, la SORAPEC à Fontenay-sous-Bois.
Les résultats furent prometteurs : 1 kW mais pas d'autre matériau pour le catalyseur que le platine. Dans le cadre de cette étude, on a réussi à minimiser considérablement le taux de platine nécessaire. On est passé de 20g de Pt/kW en 1991 à 1g de Pt/kW en 1995.

BBV : Est-ce que la commission européenne a joué un rôle dans ce programme ?

JCG : En 1993, la Commission européenne à Bruxelles soutenait le laboratoire de PETTEN aux Pays-Bas dans la création d'un Brass Board, un banc d'essai, un système roulant pour tester les éléments constitutifs d'une pile à combustibles. Ce projet était en cours de réalisation au Centre nucléaire néerlandais.
Peter Zeegers, scientific officer de la DGXII à la Commission européenne (plus tard il y sera directeur) soutenait de tous ses efforts le désir de passer aux applications. Quelques mois plus tard, fin 93, la Commission lançait un appel d'offres incluant les véhicules à piles à combustibles.
Deux ingénieurs furent recrutés : un électrotechnicien de l'ENSI de Lyon, un électrochimiste du LEPMI de Grenoble qui avait fait un post-doc chez Siemens. Cette petite équipe a travaillé durement et s'est vraiment investie dans le projet.
On a divisé le véhicule en 5 packages :

- piles à combustibles
- système des auxiliaires (qui entoure la pile à combustible)
- réservoir à hydrogène liquide
- motorisation électrique (à l'avant)
- véhicule intégré
Pour chaque package on a identifié trois partenaires potentiels et on a choisi l'un des trois.
Chaque partenaire devait apporter sa contribution financière au projet.
- Pour la pile à combustibles, on a contacté Elenco en Belgique, Siemens en Allemagne, DeNora en Italie, à Milan. Finalement, on a choisi De Nora. [1]
- Pour le réservoir d'hydrogène, on a rencontré Air Liquide en France, Linde en Allemagne, Messer Griesheim en Allemagne. Pour stocker l'hydrogène à –250°C, il faut des réservoirs cryogéniques à haute isolation. Les conditions de sécurité sont drastiques.
- Pour la motorisation électrique, on avait le choix entre les technologies émergentes ou déjà exploitées. Notre recherche portait sur la taille du moteur et son rendement. On a pressenti Siemens, AUXILEC en France (expert en véhicule électrique) et Fichtel und Sachs en Bavière.
- Pour le système auxiliaire, il fallait une expertise en systèmes complexes, dynamique des fluides et thermodynamique ; plus une expérience dans le maniement de l'hydrogène. On a consulté Vickers Shipbuildings Ltd, en Ecosse (VSL), Ansaldo Ricerche en Italie, fabricant d'autobus et de centrales.

Dans tous les cas nos critères de choix étaient :

- prestation maximale au meilleur coût
- compatibilité entre les partenaires
- disponibilité et réactivité
Par exemple, Linde proposait un réservoir plus cher que Air Liquide, lui-même plus cher que Messer Griesheim à 400 000FF. On a choisi Air Liquide, non parce qu'ils sont français mais parce qu'ils offraient une prestation en plus pour la circulation de l'air.
La compagnie écossaise VSL a été écartée car ils avaient déjà signé un accord avec Ballard, une société canadienne concurrente sur le terrain des véhicules à piles à combustible. Pour orienter l'architecture du véhicule on a choisi Volvo car il offrait la simulation numérique qui évitait les tâtonnements.

On a ainsi constitué une équipe de 6 partenaires [2] qui fut agréée par la Commission européenne en 1994. Le budget était de 4.3 millions d'euros (environ 25 millions de FF) pour l'ensemble du projet. La commission européenne versait 2.5 millions d'Euros en trois ans, le reste étant à la charge des partenaires.

Le résultat : Fever, un véhicule qui pèse 2200 kg, capable d'une autonomie de 500km à émissions de polluants nulle, mais dans lequel l'habitabilité n'est pas préservée.
L'équipe technique, chez Renault, était très faiblement dimensionnée (2 ingénieurs et 2 techniciens) puisque, dans un projet multipartenaires, chacun d'eux assume sa part de la charge sectorisée.
Certains partenaires ont fait plus que leur part de travail, en particulier le Centre Energétique de l'Ecole des Mines à Sophia-Antipolis dirigé par Patrick Achard, assisté de Rudoph M. Meyer, qui venait de finir sa thèse. Ils étaient en charge de la validation de la pile à combustible ; ils l'ont expérimentée dans leur labo. Luc Rouvère a conçu le système autour de la pile en faisant un calcul de gestion optimale de l'énergie par simulation numérique.
Les méandres administratives de l'homologation on conduit Air liquide à livrer le réservoir avec un an et demi de retard. Il a fallu obtenir une prolongation du projet de 1997 à 1998 et engager des ressources et dépenses très supérieures à celles du contrat initial.

BBV : Est-ce que la simulation joue un rôle décisif à ce niveau ?

JCG : Oui elle évite bien des tâtonnements.

BBV : Quels étaient les projets concurrents ?

JCG : Que se passait-il dans le monde entre 1994-98 ? En 1994 Daimler-Benz annonce Necar 1 : un camion de 3,5 tonnes avec seulement 2 places. L'hydrogène est comprimé et l'autonome inférieure à 100km.
En 1995, Daimler sort Necar 2 : l'espace libre est plus grand : 6 places, car ils intègrent la pile à combustibles et le système dans le plancher tandis que le réservoir à hydrogène comprimé est logé dans un double plafond.

BBV : Et quel est l'électrolyte utilisé ?

JCG : Dans notre cas c'est un polymère conducteur de protons, un polysulfone fluoré Toutes ces piles sont au Nafion ou a un dérivé de Nafion.
En 1996 Daimler Chrysler présente le Necar 3. Une classe A. La pile est dans le double plancher avec un reformer qui transforme le méthanol en hydrogène. Le reformer c'est un réacteur avec catalyseur dans lequel on introduit du méthanol avec de l'eau et il sort de l'hydrogène, du CO et du CO2 et de l'acide formique. L'avantage c'est que l'hydrogène est produit à bord mais le méthanol est un neurotoxique. Ce véhicule a été présenté au salon de Francfort.
Fin 96-début 97, Daimler Chrysler présente Necar 4, toujours une classe A. Cette fois, ils ont adopté la solution de stockage d'hydrogène liquide à l'arrière. L'effort de R&D consenti à l'époque représentait 900 millions de francs et 100 personnes travaillant pendant 7 ans.

BBV : Y-avait-il d'autres concurrents sérieux ?

JCG : Toyota a sorti RAV 4 : un véhicule à fuel cell avec un prétendu reformer de méthanol. Cela a fait beaucoup de bruit. En 1998, Daimler a pris une participation forte dans le capital de Ballard avec Ford pour une joint venture de 4 à 5 milliards avec promesse de produire un véhicule en 2004. En 1999, Toyota proclame dans un press release : les Fuel cells vehicles existent mais n'ont pas de marché. Nous gardons cette technologie en stand-by en attendant que le marché s'ouvre.

BBV : Chez les Français, qui est en course vers la pile à combustibles ?

JCG : Peugeot avait engagé la recherche initiale avec Renault. Ils ont initié leur programme de recherche appliquée en reprenant certains des partenaires de FEVER. Et comme nous ils ont eu des ennuis avec Ansaldo. Ils ont un excellent service de communication, si bien qu'aujourd'hui ils apparaissent comme les leaders dans le domaine, les maîtres de cette technologie en France.

BBV : Est-ce que le projet est poursuivi chez Renault aujourd'hui ?

JCG : Maintenant le pôle lourd est pris en charge par Nissan avec 100 personnes. Ce fut une expérience passionnante. Tout le monde est fier d'y avoir participé. Un très beau résultat si l'on considère que ce fut le point de départ, l'acte fondateur d'un grand programme de véhicules à piles à combustibles avec Nissan.
Fever est un laboratoire roulant, un mulet de démonstration ce n'est pas un véhicule. On ne peut pas le mettre entre les mains de tout le monde sans formation. Un prototype permet seulement de valider les caractéristiques réalistes d'un concept.

BBV : Quelles sont les voies poursuivies aujourd'hui ?

JCG : La voie du reforming de carburant, méthanol, essence ou kérosène. Tous familiers des constructeurs automobiles. Mais je pense que la solution ultime sera le stockage d'hydrogène. Le problème c'est le refuelling.

BBV : Y-a-t-il des programmes pour équiper des infrastructures routières ?

JCG : C'est une décision communautaire. Il y a des pressions de la part des milieux automobiles, des Etats. Démarche assez bizarre. L'impulsion la plus forte vient des Allemands mais les Verts ne voient pas que le véhicule électrique ne fait que repousser le problème de la pollution sur la production d'électricité propre. Pour produire de l'hydrogène il faut de l'électricité donc peut-être du nucléaire.

BBV : L'objectif 2004 est-il toujours réaliste ?

JCG : Une démonstration est prévue en 2004 en Californie : une petite flotte de 10 véhicules gérés par des instances bien choisies sera mise en circulation et Renault-Nissan enverra 3 véhicules.
Mais force est de reconnaître que le Mandate du zéro emission émis en 1992 par le Clean Air Board de Californie a été sérieusement révisé à la baisse. On acceptera les véhicules hybrides et mêmes le véhicules à gaz naturel bénéficieront d'un crédit. La Californie a fait beaucoup d'ouvertures pour ne pas se déjuger sur la date fixée 2003.

BBV : Le zero emission est-il une utopie ?

JCG : “The zero emission vehicle is a vehicle for which electricity has been produced in the next state”. Les USA produisent l'électricité la plus pénalisante en émissions de polluants. La deuxième électricité la plus sale est celle du Danemark. Elle est produite à partir des fuels lourds très soufrés.
Le centre ECODEV du CNRS a évalué l'émission de CO2 amont et aval pour diverses catégories de véhicules suivant les pays. Le véhicule électrique génère du CO2 pour la fabrication d'électricité. Kangoo électrique conduit à la production de 17g de CO2 par km contre 160 g pour un véhicule à essence. Mais aux USA un véhicule électrique produit 115g de CO2 au km.

BBV : Alors la solution de réformer le méthanol n'est-elle pas plus réaliste ?

JCG : On a 80% de rendement et le bilan global de CO2 n'est pas meilleur que celui d'un bon moteur Diesel. Le bénéfice serait de 15%. Le jeu vaut-il vraiment la chandelle ?

BBV : Ne pourrait envisager d'autres concepts ?

JCG : On poursuit des travaux sur le véhicule à usage partagé, sur le véhicule en libre service.

BBV : Ces alternatives sont-elles utopiques ?

JCG : Pas du tout. En Grande Bretagne 40% des véhicules sont achetés par des loueurs. Les gens louent au lieu d'acheter. Ce n'est pas inintéressant.

BBV : Quels sont alors les verrous qui empêchent l'essor du véhicule électrique ?

JCG : Verrou technologique surtout.

BBV : Le verrou ne serait-il pas social ? Y a t il une demande ?

JCG : Les gens veulent un moyen de transport, pas cher, confortable et générateur d'image positive, ils veulent ne jamais lever le capot. Mais cela peut changer car le symbole de la voiture commence à évoluer. Le volant comme symbole phallique c'est latin. Or nous devenons de plus en plus nordiques dans nos goûts. On conduit calme, d'où le succès grandissant de la boîte de vitesse automatique. Cette évolution des goûts peut amener quelque chose, un changement dans le concept de l'automobile.

BBV : Renault a-t-il entrepris des campagnes de sensibilisation du public pour favoriser les carburants alternatifs ?

JCG : Le seul moyen est de convaincre les policy makers qui influenceront les acheteurs de véhicules particuliers grâce à des incitations fiscales. Prenons l'exemple du GPL, trois fois plus propre que le véhicule à essence. La Direction de Renault a engagé une grande campagne de médiatisation, avec intervention au Parlement, lobbying. Suite à quoi la loi de finance de fin 95 a prévu une baisse de 1F sur le litre de GPL. Cette mesure, entrée en vigueur le 2 janvier 96, a mis le litre de GPL à 2.75 F contre 5.50 pour le litre d'essence. Du coup les chiffres de vente de véhicules au GPL ont augmenté rapidement : de 20 000 à 40 000 en un an et 125 000 aujourd'hui. On a donc multiplié par 6 en 5 ans.
Autant des compagnies que des particuliers achètent ce genre de véhicules pour l'image de marque : Danone et Darty, par exemple.

BBV : Comment voyez vous l'avenir des piles à combustibles dans l'automobile ?

JCG : A court et moyen termes, les véhicules conventionnels vont continuer avec une petite part de marché pour le GPL et le gaz naturel. L'avenir proche c'est l'hybride moteur thermique avec une assistance électrique intégrée. Cela fait gagner en consommation. Et l'objectif premier c'est réduire la consommation.
Le véhicule électrique reste un produit d'image. Le véhicule à pile à combustible ? Peut être, vers 2010. Le marché commencera par les minibus et les transports en commun. En tous cas , tous les constructeurs automobiles investissent parce qu'ils veulent posséder la technologie pour le cas où cela deviendrait le véhicule d'avenir.
Mais ce sera un processus lent de conversion et la conversion ne sera jamais totale. Même les Allemands les plus avant-gardistes ménagent un segment de parc de 15% pour les piles à combustibles.

BBV : N'y-a-t-il pas des moyens d'influencer la demande ?

JCG : Il ne faut pas inverser les objectifs et les moyens. L'objectif est le transport des personnes et des biens, confortable, rapide qui donne satisfaction au client. Le véhicule n'est qu'un moyen et non une fin en soi. L'objectif est de ne pas changer les habitudes de conduite. Le client ne veut pas savoir ce qu'il y a sous le capot. Le véhicule électrique n'est pas satisfaisant parce que la physico-chimie des batteries a trouvé ses limites dans le tableau périodique. Tant que la recharge exigera plus d'un quart d'heure, il ne peut remplir les objectifs de marché large que nous visons.

BBV : Mais si une volonté politique rendait le véhicule plus satisfaisant ?

JCG : La politique nationale ne peut rien car le marché est mondial. A l'heure actuelle Renault-Nissan produit 4 millions de véhicules et l'objectif pour 2010 est 8 millions. Cela nécessite une expansion mondiale sur le marché américain, africain, asiatique...Une faveur fiscale nationale n'est pas un motif assez puissant pour investir trois milliards dans un projet de R&D. La Mégane a coûté 9 milliards d'investissement sur 3 ans, amortis en 5 ans.

BBV : Est-ce le manque de retour sur investissement qui freinent les recherches sur le véhicule électrique ?

JCG : Le retour sur investissement est difficile à évaluer. Notre programme de recherche a eu un résultat modeste mais il a été le tremplin d'un grand projet, engageant plus de 100 personnes. Si dans 10 ans, il n'y a pas de marché c'est un flop. Mais s'il y a un marché ce sera considéré comme un investissement très rentable car bon marché.

BBV : Le véhicule à pile à combustible est donc un futur possible ?

JCG : Qui sait ? Je ne peux pas prédire l'avenir. Politiquement nous n'avons pas le droit d'être absent de la course. S'il y a une chance une seule, alors il faut y aller.

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[1] This electrochemical company was founded in 1923 by Oronzio de Nora. Today, De NORA SPA designs and delivers complete plants world wide for electrochemical and electrometallurgical industries.

[2] Ces 6 partenaires sont :

- Ecole des mines (Optimizing operating parameters) was in charge of constructing a test bench and simulation models in order to determine the optimal operating parameters of the fuel cell.
- Ansaldo Ricerche : design, assembly and test of the Power Module.
- Air Liquide in charge of the hydrogen tank, hydrogen recirculation and refuelling facility.
- Volvo TD in charge of i) energy management, ii) battery evaluation and specification, iii) safety study.
- De Nora SPA in charge of the design, manufacture and test of the Solid Polymer Fuel Cell stacks.
- Renault as leader of the project was responsible for the choice of the electric motor and the specification of the air compression system. Renault designed the architecture and assembled the demonstrator.

Pour citer l'entretien :

« Entretien avec Jean-Claude Griesemann », par Bernadette Bensaude-Vincent, 24 février 2001 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article123.

—

Entretien avec Jean-Claude Griesemann, par Bernadette Bensaude-Vincent, 24 février 2001

Lieu : France

Support : non communiqué

Transcription : Bernadette Bensaude-Vincent

Edition en ligne : Sophie Jourdin

FUJITANI Shin, 2002-09

Sophie Jourdin — 2011-10-28T12:13:19Z

Shin Fujitani

Research Manager, Sanyo Electric. Co. Ltd., Soft Energy Company, R&D Division, Energy R&D Center

BERNADETTE BENSAUDE-VINCENT (BBV) : In which discipline did you take your degree ? your Ph D ?

Dr. SHIN FUJITANI (DF) : I took a doctorate in metallurgy.

BBV : How and when did you come into industrial research ?

DF : I joined Sanyo in 1982 just after I finished graduate school.

BBV : Which field is your specialty ?

DF : Metallurgy, electrochemistry and battery.

BBV : Did you specialize in one field or did you change your research subject ?

DF : Before I joined the company, I had majored in metallurgy. Since I joined here, I have been engaged in battery R&D based on metallurgy and electrochemistry.

BBV : Did you conduct your research in contact with university or national laboratories ?

DF : I have worked on governmental contract under a collaboration with a national laboratory for about 10 years.

BBV : How do you plan your research ? What is a long term research project for you ?

DF : Short term projects are planed in accordance with demands from existing markets. Long term ones are planed to help the short term projects going successfully. These may be a general idea, which my current R&D field, battery technology, has followed in the company.

BBV : We learn a lot from success but failures are even more illuminating for historians. Would you tell us about a case of failure in your career or in your field ?

DF : Among many failures, the most significant in my view is the 10 year project that I mentioned above, conducted in collaboration with a nationaly laboratory. I certainly obtained new chemical views and new materials but they found no applications. R&D in a targeted area did not work well and finally this project did not result in important industrial contributions.

BBV : Could you give me a few details about the organization of your laboratory : how many people are working here ? Is there a clear division of labour ? of research themes ? What are the disciplinary affiliations of the people in your laboratory ?

DF : I am afraid that I cannot tell you how many people are working here because of confidentiality. People are divided according to the specific theme they are working on, so that their responsibilities are clearly defined.
The researchers in my lab. have different disciplinary backgrounds, in electrochemistry, in chemical engineering and in a variety of materials sciences, organic for some of them and inorganic for others.

BBV : Where do the financial resources come from ? Do you have internal reporting ? Regular meetings ?

DF : The financial resources are all covered by the company. Therefore, I am obliged to report results on my R&D activities sometimes in the regular meeting weekly, monthly and annually.

BBV : Do you have financial constraints in purchasing instruments ?

DF : I am afraid that the notion of “financial constraints” is a little vague for me. The budget of R&D is determined for each purpose, e.g. ; for purchasing consumable supplies and materials, for investing plant and machinery, for the expenses of business trips , etc., and the total amount is determined in consideration of cost performance and risks of the R&D to the business, and the business conditions as well.

BBV : Publishing or patenting ? What is the priority ?

DF : Patenting is the priority. Ne number of patents largely exceed the number of publications in journals as well as of oral presentations in conferences.

BBV : Do you attend international conferences ? Which ones ? In which countries ?

DF : Yes we attend conferences everywhere as long they cover interesting topics in my field. Personally, I have attended conference in the USA and Canada as well as in some European countries.

BBV : Do you have international collaborations ? In which countries ?

DF : Some R&D collaborations in EU and US are now underway.

BBV : Did you notice different cultural research styles ?

DF : Yes, I did. Research abroad starts at a much more fundamental level than our researches in Japan, Their value and their results are consequently often more praised and amired than our Japanese contributions.

BBV : Do you think that the materials generic perspective, as it is based on a system approach between structure, properties, performances and process, is useful for your research ?

DF : Yes, I think it is extremely useful as long as it helps defining in some way the potentialities and limitations of the materials' functions for specific application devices, e.g. for battery performance in my case.

BBV : What is the place of Materials research in your country ? In terms of economic importance and social prestige or public image ?

DF : The centers where Materials researches are performed are scattered all over Japan, including universities, firms and public institutions. There are two major poles of national laboratories : one is in Tsukuba, Ibaraki prefecture 1hr away by train from central Tokyo and the other one is found in Ikeda, Osaka prefecture.

BBV : Where would you locate the leading centers in your field ?

DF : My lab is now located in Kobe, Hyogo prefecture. I think it is a good candidate for ranking among the leading centers in the field of batteries. Its importance may partly be due to the fact that Kobe is one of the most attractive big cities in Japan for educated people.

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Pour citer l'entretien :

« Entretien avec Shin Fujitani », par Bernadette Bensaude-Vincent, septembre 2002 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article120.

—

Entretien avec Shin Fujitani, par Bernadette Bensaude-Vincent, septembre 2002

Lieu : Sanyo Electric.Co.Ltd., Soft Energy Company, R&D Division, Energy R&D Center

Support : non communiqué

Transcription : Bernadette Bensaude-Vincent

Edition en ligne : Sophie Jourdin

ARRIBART Hervé, 2001-02-19, 05-29, 02-20

Sophie Jourdin — 2011-06-16T07:31:17Z

Hervé Arribart is the Scientific Director of Saint-Gobain Recherche, an international company of French origin with an emphasis on glass manufacture. He took his PhD from the Ecole Polytechnique in Paris in the mid-1970s and subsequently researched ionic transport using nuclear magnetic resonance. In the late 1970s he worked with Jean Rouxel's group at the University of Nantes. In 1981 he joined the company Elf to work in research and development. In 1985 he moved to Saint-Gobain, where at first a large portion of his research was closely related to the practical problems of production. In 1990 he started a laboratory (a joint venture of Saint-Gobain and the CNRS) on the basic science of glass surfaces, using a diverse set of tools and especially the Atomic Force Microscope. In 1999 he moved to the more managerial position of Scientific Director. Hervé is also on the staff of this project.

2001-02-19 :

HERVE ARRIBART (HA) : I studied at the École Polytechnique in Paris. The selection to the school is done mainly on mathematics. But during my studies I learnt to appreciate physics in particular. I decided to pursue research in solid-state physics. It was a good place to study physics. While in my last year as an undergraduate I did a Diplome d'Étude Approfondie in parallel (an intermediary between an M.Sc. and a PhD typically done for a year before starting one's PhD studies). In Orsay, near the École Polytechnique, there is a very famous place in solid state physics, a lab started by Jacques Friedel - a great name in solid-state physics. I followed this course and afterwards I did the PhD at the École Polytechnique in the field of condensed matter physics. In principle I ought to have started with a topic distant from materials science. I extracted spin-polarized electrons from semiconductors. This was in 1974.

ARNE HESSENBRUCH (AH) : How did one extract spin-polarized electrons in 1974 ?

HA : It is true of all solids, but in semiconductors it is especially interesting that when light falls upon a surface there is a coupling between the spin of photons (in classical physics : the polarization of light) and the spin of electrons. Electrons in the upper layer absorb light photons depending upon the spin. If by some technique you can extract electrons from the conduction band of the semiconductor, you can find ways to select electrons of specific spins. This was quite important at the time because at big-science institutions such as LEP [Large Electron Positron collider] or SLAC [Stanford Linear Accelerator Center], there was a need for spin-polarized electrons. And of course you then needed solid-state physics to do it. But the man who in principle was my supervisor decided to do something else. His name is Claude Weisbuch, and he is now a good friend of mine. For a few years he was the scientific director of the French Department of Defense. He is still working in solid-state physics, in the optics of semiconductors. But he decided to do something else and Bernard Sapoval, another professor at the lab, proposed that I work on new materials. At that time there was little contact between solid-state physics and solid-state chemistry. The idea was to link up with chemists. This is why very early on in my career I had contact with chemists. We worked with Parisian solid state chemists on a new material. We found a new way to draw single crystals of an already existing material. It was very nice because we could examine transport and NMR phenomena. And the material, a copper vanadium sulfide exhibited astonishing properties : a large spread of conductivity that one can measure in a standard experiment. We suspected that this was due to mixed conduction properties. Mixed conductivity refers to conductivity by both electrons and ions. The experiment appeared to verify our a priori suspicion. This gave me the possibility to present a model for mixed conduction in this material and to understand the influence of ion transport and electron transport. I also used NMR in order to understand which ions moved. It turned out that the copper ions moved. So, this was the subject of my first thesis. At the time, in France, there were two theses. The first one was called "thèse de troisième cycle". The second was the "Docteur es sciences". This degree does not exist any longer. The thesis that is done now is shorter.

I decided to continue to work with chemists. I decided to combine NMR and transport measurements. I changed my collaborators, turning to two different groups. In my PhD there had been two chapters on NMR. But I wanted to study proton transport. I had two reasons. One was that protons give a strong NMR signal. The second reason was that two reasons had been given for proton transport. In one, protons move in individual jumps. In the other the proton is a part of a more complex molecule such as the ammonium ion (NH4+) or hydroxonium (H30+). In the former case we can see the transport phenomenon as a result of molecule rotation and proton jump. The molecule would turn and the proton jumps to the neighboring molecule, which again turns and so on. This was called the rotation-jump model. The second model was for the whole complex ion to jump. This was called the vehicle model because the whole molecule acts as a vehicle. So I worked with one group of chemists in Nantes, at the Institut de Matériaux de l'Université de Nantes. It had just been created by Jean Rouxel, a chemist. With them I worked on a substance called antimony acid - a solid. I was able to show using NMR that transport occurred in this case with rotation-jump. Protons used H30+ as a complex rotator. I was also able to show that the jump was due to quantum mechanics within a certain temperature range. It was not the usual ion transport of classical mechanics.

AH : A tunneling effect ?

HA : Yes, this is one aspect of protons, because protons are very light ions allowing for this quantum effect. The other material I studied was ammonium beta alumina. This was the standard beta aluminium in which the sodium had been ion exchanged with ammonium. This material was very interesting from the perspective of NMR. All kinds of ionic motion took place at different temperatures. At the lowest temperatures, that of liquid helium (1-4K), there was rotational quantum motion. As the temperature increases the motion becomes classical.

AH : If I may make a comparison with Stanley Whittingham here. You were working on some of the same materials, you were using some of the same tools (NMR), but you were asking very different questions, right ?

HA : Yes, that is true. I was not at all involved in the application. For two reasons : French chemists were interested in materials and did not look to the application. And chemists were between me and the application, so I had no contact with attitudes such as Whittingham's. I was very happy working on the solid-state physics problems.

AH : And we are talking about the late 1970s now ?

HA : Yes, I began the proton transport research, I think, in 1976.

AH : And it went on for how long ?

HA : For five or six years.

AH : And you lived in Nantes ?

HA : No, I remained in Paris while collaborating with the Nantes group.

AH : Were you employed in Nantes ?

HA : No, not at all. At the beginning I was employed at the Ecole Polytechnique as a research assistant, and then I was hired by the CNRS - in 1977.

AH : So, the CNRS paid your salary, you were able to do basically whatever you wanted, and you collaborated with Jean Rouxel and coworkers because you found it interesting ?

HA : Yes. It was a chance to work with an outstanding chemist. French chemists were really very good. The problem, as we just said, was that there was little interest in application.

AH : What did you do next ?

HA : After my PhD thesis, I found it interesting to go to industry.

AH : I imagine that there were many advantages and disadvantages to leaving academia for industry. For instance, where was status greater, what paid better, where were working conditions better ?

HA : First of all, it was rare, even more so than today, for CNRS people, or people within the public system, to go to industry. I cannot give you a clear answer about my motivation - it was not even clear to myself at the time. I did get a higher salary in industry. I also had personal reasons for leaving Paris and going to the Elf company. I went to an Elf research lab in the Southwest of France, in a very nice place in the Pyrénées. I had small children at the time and it was much better for them to grow up in the countryside and in a very nice climate. I was also curious. So the decision involved many elements. And anyway, it was not irreversible. The CNRS allowed me to take a three-year leave after which I could have gone back. With regard to the working conditions : I was of course less free than I had been at the CNRS, but I found it more stimulating because there were a lot of different problems on the horizon, arriving almost every day. We could easily get the necessary equipment at the CNRS and at Elf, so there were no differences there.

AH : The restrictions at Elf had to do with what you were allowed to study ?

HA : Yes.

AH : What did Elf want you to do ?

HA : In principle I was hired to work on solid-state sensors. Because it was not in the direct line of my previous work I proposed that I work on solid-state sensors and ion conduction. We developed a family of sensors named ISFETs (Ion Sensitive Field Effect Transistors). It was a new kind of transistor at the time but now it is very common. You control the electrode using field effects, opening and closing the circuit between the two other electrodes. This is the way the transistor works. My idea - not an original one - was to replace this way of controlling the electrode, the gate, to replace it with a membrane, selective to such and such an ion. If you put the device in a solution containing the ion for which you have designed the system, the membrane will be charged. This charge will change the state of the solid-state transistor. It worked all right for protons. We could use the device to measure pH and afterwards we just had to change the nature of the membrane, choosing a different solid electrolyte, such as calcium fluoride.

AH : Your toolkit remained the same and you still used NMR ?

HA : Not NMR, but yes. You need large samples in order to do NMR. So it was mainly electrochemistry and surface analysis. This was between 1982 and 1985. But as I told you, in industry new projects can arrive almost every day. I had developed some skills in electronics using instrumentation at the École Polytechnique. Elf applied for a patent for a medical analysis system, a small instrument to be sold to private practitioners, as opposed to hospitals. This had nothing to do with solid-state ionics. But the people working on this project needed someone who knew about electronics, and so I got progressively more involved. After one or two years it had become my main project. This worked very well. I was very proud to design an electronic system that required no manual setting. It was set in the factory forever. This was a critical issue, because we thought that doctors could not be expected to deal with electronics - and I am sure that we were right in this. So there was nothing to check or calibrate - the system was self-calibrating. So it worked very well, and after only two or three years Elf built a plant and people were hired. But in 1984 and 1985 there were big changes in chemistry. And there was a great redistribution of all chemical industries. And Elf, that had been an oil company, in this period expanded to become also a chemical company. As a result a lot of the more diversified lines of business lost in importance. Many projects like ours were discontinued. But because we were already quite advanced we found a way to keep going. In fact it was Dupont de Nemours that found that our system was complimentary to some of theirs. The result was that Elf shipped the patent and everything else to Dupont. For a few months I considered following the project to Dupont and to the United States. In the end I decided against. I still wanted to work in solid-state physics and not to work completely in the instrument making business. But for one or two years I continued as a consultant.

2000-05-29 :

HA : For both personal and professional reasons, I decided to stay in Paris, and then Saint-Gobain offered me a position, working in a new research field : polymer adhesion on glass and other materials. It was a new topic for me too. At the time adhesion was not even considered a science. It was before Pierre-Gilles de Gennes's Nobel Prize in polymer adhesion [1991]. It was rather considered an art. Even though I had no background in the field I was interested. What interested me in the Saint-Gobain proposal was that real breakthroughs were to be expected in the science of adhesion when two materials are brought into contact. In fact this was my first real industrial experience. Of course CNRS had not been an industrial experience at all, and even at Elf I was always in the research lab. As I explained, my work at Elf had nothing to do with the industrial activities. I never visited factories. At Saint-Gobain I had to do this, at least in the beginning.

AH : Did you not say that your development of the medical analysis system resulted in the setting up of a plant ?

HA : Yes. I did participate in the design of the plan, in order to make it efficient. But I had no role in the plant itself after construction. It was also a small plant for high-tech activity.

AH : You had nothing to do with the fabrication side of it, situated in the plant – merely the R&D before the plant became functional ?

HA : Yes, exactly. Saint-Gobain of course has many plants all over France and Europe, and even the United States. But at that time, the company was still franco-français [French through and through] in its general spirit and culture, despite the many factories in other countries. There were only French directors and the system was based on the French system of education. There is a hierarchy from the École Polytechnique through the École des Mines and the École Centrale to lesser schools, and you carry the status of your school within you for the rest of your life. I remember that I strongly felt the weight of tradition when I first joined the company. It is true that winds of change were already blowing then, but they were barely noticeable and needed a couple of years before really expressing themselves. But eventually the company changed its culture, and now the company considers itself an international one. I think a deep change has taken place during my 15 years with the company.

So, anyway, this was the first time I gained experience of the industrial aspect of research. My first task was to examine and synthesize different kinds of adhesion in Saint-Gobain's products and processes. I decided to simultaneously pursue fundamental reflection and a practical approach, helping the factories improve their processes. This was a very instructive experience. I learnt many things although I am not sure that I helped the factories all that much. I certainly learnt for myself that I preferred to stay within R&D and not to progress into production. On the fundamental side, I developed a network of contacts in public labs in France and the US. This became useful later on. After three years in the field, and having created a small research lab, I decided to gain some distance from the practical aspect of my work. It was also obvious to me that fundamental research was required first. Progressively the idea came to me to propose the creation a special laboratory dedicated to the basic aspects of polymer adhesion - and of course also to related issues such as the surface science of glass. But I knew that Saint-Gobain was not ready to have a laboratory for basic science by itself, so my idea was to set up a lab jointly with the CNRS. This was in 1988. From the administrative point of view this was feasible : a number of such joint ventures already existed, an example of which is Rhône-Poulenc. Of course I had to convince both Saint-Gobain and the CNRS of the utility of the project which was not straightforward. Although I managed to convince Saint-Gobain in a manner of hours, CNRS needed more prompting.

AH : Would you explain the nature of Saint-Gobain's research before your proposed laboratory ?

HA : It was a quite common kind of R&D geared towards problem solving. Helping the development of new products and solving problems within production.

AH : So the research agenda was driven by questions arising out of production ?

HA : Yes, and my idea was to get a more fundamental understanding of the questions which would enable us to help with such questions in a much better way.

Figure 1. Saint-Gobain Recherche, Paris

At Saint-Gobain I had to sell the idea primarily to the Vice-President of R&D. He took the decision just before retiring. The CNRS process was more complex. It has a democratic organization where decisions are taken by committees. The members consist of both elected researchers and individuals named by the Ministry of Research. They are divided up into different scientific sections. So here I had to convince a diverse group of people, and not just one person, as at Saint-Gobain. As I mentioned, I had developed a network of relationships in the fields of adhesion and surface science and now this turned out to be useful. I knew that many people approved of my research agenda. My project was accepted without much fanfare, but it still took a while because of the administrational hoops that a proposal has to jump through within the CNRS. They meet only twice a year, and every decision has to be validated by the CNRS directors and so on. It took maybe 12 months. The laboratory started on January 1, 1990. But there was only a building and neither instruments nor people.

Figure 2. Joint lab : Saint-Gobain Recherche & CNRS

The three yellow arrows point to the units of the joint lab within the Saint-Gobain Recherche building.

In the meantime I conferred with scientists in many other labs trying to recruit people. Of course the CNRS could not order people to go, so I had to entice scientists away. I estimated that I needed three scientists from the CNRS in addition to three scientists from Saint-Gobain. Two of the latter had already worked with me, and they followed me to the new project. A further researcher came from somewhere else – it was a young Chinese woman. We also had two or three technicians and some PhD students. Altogether, it took a year or so to gather everyone together. We also had to buy instruments and the process of getting the laboratory shipshape lasted altogether something like 2 years. We began to actually do some research in late 1990. And from then on the activities progressed rapidly. In two to three years we reached a plateau of 20 people, a level that had been stipulated by the CNRS. A third of the people had come from the CNRS, a third from Saint-Gobain, with PhD students constituting the last third.

AH : Where did they come from ?

HA : The latter were doing industrial PhDs (Contrat à Durée Déterminée) with Saint-Gobain, and their salary came jointly from the French Ministry of Research and from Saint-Gobain. Of the entire staff, about half each came from chemistry and physics. It was crucial that we develop knowledge and expertise in both these fields. Later we also developed an interest in mechanical problems.

Figure 3. The SPM from Park Scientif Instrument

AH : What was the instrumentation ?

HA : There was a conjunction of the beginning of our lab with the very early days of scanning probe microscopy. This new kind of instrumentation offered a very exciting opportunity. There was a risk in this. We purchased the first Atomic Force Microscope (AFM) ever in France. We bought it from Park Scientific Instruments. Later we built the first AFM for UHV purposes. There were many people then who thought the instrument had no future, so it was a risk to invest time and money in it.

AH : Why did people think it had no future ?

HA : The objection was that it was not clear that atomic resolution could actually be achieved with the AFM. It was not until 1993 that Binnig showed true atomic resolution.

AH : Well, yes, but before he had claimed to achieve atomic resolution. In 1993 he only claimed that so far he had been mistaken and only in 1993 did he achieve true resolution. Is that not right ?

HA : Yes. But in 1993 the community was convinced. The reason I did not hesitate was that atomic resolution was not actually the big issue for our purposes. Even a resolution of 1 nanometer amounted to a great deal. Much could be done with such a resolution in the field of adhesion, and also in fracture mechanics and surface chemistry.

AH : I have the impression that since 1995 or so many people argue that atomic resolution is not really that important, and that in the early 1990s it was still considered the holy grail. So you were unusual in that you had this attitude so early ?

HA : You are right that atomic resolution had a special ring to it in those days.

AH : Did you emphasize the issue of atomic resolution in your application to the CNRS ?

HA : I am not sure. Even today, nobody has achieved atomic resolution in glass. So it would have been a hard sell, also then. The same goes for polymers. And those two were our substances under investigation.
There is a difference between STM and AFM. They obey two different logics. The STM has remained a tool of basic research, in surface science. The AFM, even early on (and this would be interesting to discuss with Calvin Quate or Gerd Binnig), there was a hope that it could be useful, for example in other fields of science, such as mine, or in technology, such as process control, microelectronics, semiconductors, and so on. Generally speaking, in early phases there are always many people who think that a novelty will never become common. We have to remember that in 1987 or 1988 solid probe microscopes were still big and unwieldy instruments. Of course miniaturization had set in by 1990, but it was a novelty. Only very few people were convinced that the AFM would become so common. Calvin Quate is one of the few. The STM has revolutionized basic research on metals and semiconductors. There was a reaction against it, because surface science was done using diffraction techniques working in reciprocal space. Surface scientists were formed in this mode of research. They resisted the change, feeling that newcomers would enter their field without the kind of abstraction that had hitherto been key to access to the field. Working in ordinary space was too easy ! Of course it has not actually become easy because the instrument has brought its own problems, and there are still people working with diffraction and in reciprocal space. The two complement each other.

AH : So this is the background against which your decision has to be seen. You went out on a limb.

HA : Yes. The beginning of my lab coincided with the first commercial scanning probe microscopes (SPMs). We had to grasp the opportunity.

AH : How did you know about the AFM ? Was it a very visible instrument at the time ?

HA : No. I knew about it from publications, but in order to actually see an instrument, I had to travel to California - although I guess I could have seen one at IBM Zurich. There was an STM at Marseille, because two physicists there (Salvan and Humbert) had worked at IBM Zurich, and they had brought one back with them. But they had no experience with the AFM. So I went to the US and visited the very few labs with AFM, both academic labs and the start-up companies of PSI [Park Scientific Instruments] and DI [Digital Instruments]. At Stanford University I met Calvin Quate and at UC Santa Barbara I met Paul Hansma.

AH : Was there a relationship between Paul Hansma and DI ?

HA : I don't remember. But at any rate it was not as close as the one between Quate and Park. I think Park was a former student of Quate's.

AH : So you purchased an AFM from Park. What about the other kinds of instrumentation you purchased for your lab ?

HA : Yes, we had to get other instruments, partly because it took a long time for the AFM to arrive. I had to go to the US to compare the DI and the Park instruments, and I discussed it with the physicists and chemists in our lab before ordering, and then we had to wait for the delivery – maybe 4 months or so. We got a 40% discount, because we were the first French customers, and they hoped that we would open the French market for them. I had very good discussions with Quate, and I think he trusted me to be a good advertisement for him in France. I think we paid 400,000 French Francs, so that the catalogue price was in the order of 800,000 French Francs [approximately US$100,000].

We bought also an infra-red spectrometer, in order to study molecular grafting on oxides. This we used as a complement to the AFM. And as I said in a previous part of the interview, our approach was to combine the traditional surface science (very clean surfaces) with “true surfaces” interacting with the environment. The infra-red spectrometer, XPS (X-ray Photoelectron Spectroscopy), and LEED (Low-Energy Electron Diffraction) were good tools for the traditional surface science approach working in UHV Ultra-High Vacuum). And also HR-EELS (High-Resolution Electron Energy Loss Spectroscopy). Our choice was risky, but it turned out to be correct. Our decision to build bridges between the two approaches was taken in 1992 or 1993. Quite early on in our project we built a surface force apparatus (SFA). It is not at all an AFM – there is no concept of high resolution, but it is similar in that you can get a direct measurement of the force interacting between two objects only a few Ångstroms apart. The idea is to make the measurement quantitative in order to study whether the interaction is due to van der Waals or electrostatic forces. In fact this project took six years – not for technical reasons but simply because we had to get the right people.

AH : Each instrument had its strengths and weaknesses in terms of resolution and the scale of the surface analyzed. And each instrument required special skills. The AFM, for example, requires quite some expertise to disentangle signal from instrumental artifacts, right ?

HA : Yes, artefacts were a real concern at the beginning, when we all had very limited experience. We had to pay much attention in order to ascertain the results.

AH : Can you explain how one separates signal from artefact ?

HA : There are different kinds of artefact. One that now seems quite natural but was hard to understand then is the tip effect. If the surface under examination has sharper topographic features than the tip, then the tip will be imaged rather than the surface. We had trouble with this kind of artefact. In fact, when studying tin oxide deposits on some substrate we got very nice images that we at first interpreted as small crystals having the similar orientation. We were very excited to find a growth mechanism of specific orientations on isotropic surfaces such as glass. I decided to present this result at a small meeting in Davos, Switzerland. The topic there was in fact “The AFM for Technological Applications”. Famous scientists attended, including Calvin Quate, Jim Gimzewski, and Heinrich Rohrer. There were only some 10 people there, because this was very early, maybe 1991. The night before my presentation, I began to wonder that the result was really too beautiful to be true. I telephoned my lab and asked people there to turn the sample by some angle and do the experiment again. That way, the features should have changed if they belonged to the surface. But they did not, and so we knew that the features belonged to the tip. So I did not present that particular slide in my talk.

AH : So rotating the sample by some degree is one way of identifying artefacts.

HA : Yes, that will eliminate this kind of artefact, the tip effect. There are also adhesion artefacts, some of which have been solved in the meantime thanks to new recording techniques such as the tapping mode.

AH : Digital Instruments has a patent for the tapping mode, right ?

HA : Yes.

AH : So the Park instrument that you bought did not have the tapping mode ?

HA : No it did not. The tapping mode did not become available until 1993 or so. Later on, Park Scientific Instruments did do something similar, but they may not call it tapping mode. The DI patent covers the name. And in the straightforward contact mode many artefacts were possible ; for example when looking at soft materials and polymers surface scratches easily occur. If you do that you image the substrate only. One way to identify this effect is to scan again with a smaller tip-surface interaction. In some cases you will find miniature small squares where the surface had been damaged in the course of the first scan. Some artefacts are very common, others are quite specific and harder to identify.

AH : In what you have explained, the identification of artefacts is internal to the instrument itself. It is not that you can go and compare the results of an AFM scan with those from a different instrument ?

HA : You can change the tip, and you should identify artefacts unless you are very unlucky to get the same tip. Everybody understood that the AFM has great potential not just as an imaging instrument but also to measure adhesion, hardness and so on.

AH : Using force-distance curves ?

HA : Yes, force-distance curves. This turned out to be very useful for us. For instance in order to understand the electrostatic interaction between oxide and a silicon nitride tip under water. This was original work. For example, in polymer adhesion we checked if it stayed on the substrate and what scratching would do. Of course such ideas were floating around at the time.

AH : Were you important to the subsequent spread of the AFM in France ?

HA : Yes, people came to our lab. Another lab, at the Institut Curie, that got an AFM at almost the same time. For a while we were a small community but then gradually we grew larger and larger. Yes, we were the pioneers. It was exciting.

2001-02-20 :

HA : I went with one of my sons who was 11 years old at the time to see Park Scientific Instruments. There were no more than 10 people working there, in fact I think it was more like three. It was very small and familial. We discussed and had tea. I enjoyed discussing with these people. It was nothing like an established company.

AH : What did it look like ? Did they work out of a garage ?

HA : Something like between a home and a garage. It was a small house. Even Digital Instruments started out like this. Already in those days DI, and especially Virgil Elings, was much more commercially aggressive, but they were very small too at the time.

AH : Did you stay in touch with some of these guys ?

HA : I stayed in touch with Calvin Quate for five or six years, until 1996. After that I lost the contact but he will probably remember me because we had many discussions. It was curious to see his impact upon materials science. In fact it was very difficult for him to get the first paper on the AFM accepted in Physical Review Letters. Some of it was considered just a pure mechanical profilometer. It had good resolution but it was not really anything new. His project now is very interesting from what I can tell reading his articles in the scientific journals. And he really is a very nice person. Maybe the last time I saw him is when I invited him to give a talk at Saint-Gobain Recherche.

AH : So you stayed in touch with him in the early 1990s, while you were developing your own AFM. I guess the use of the AFM changed the project from what you had originally envisaged ? Did you continue using all the other tools or did you focus exclusively on the AFM ?

HA : We used the other tools.

AH : What did you buy for your laboratory ?

HA : Infrared spectrometer, XPS, HR-EELS (High Resolution Electron Energy Loss Spectrometer), LEED. Quite quickly we had three AFMs. I wanted to develop a PSTM working in the infrared but unfortunately that particular project died because the physicist we had working on it left.

AH : What journals show the history of these instruments best ?

HA : In the beginning it was mainly in the general physics journals such as Applied Physics, Applied Physics Letters, Physical Review Letters, Surface Science. Now there are specialized journals. A journal like Journal of Scientific Instruments is not so important in this respect. Langmuir is also important for soft matter.

AH : Do any of these journals have review articles ?

HA : I am almost sure that all of them do.

AH : We were talking about the various instruments you had in your lab. How did you apply them to your research project ?

HA : The idea was to have two parallel approaches. We were mainly interested in adhesion, molecular grafting and so on. One approach is the classical view of surface science, the ideal surface approach. The other is the REAL surface approach, taking the environment as a part of the system.

AH : Not working in Ultra-High Vacuum (UHV) ?

HA : Yes. But we were trying to make the two approaches meet.

AH : So when you started working with the AFM in UHV, the point was to simplify the experiment ?

HA : Yes.

Figure 4. UHV Chamber et AFM in UHV Chamber

If a probe were to be introduced directly into the UHV chamber, it would take days of pumping to achieve UHV. Instead, it is first introduced into an antechamber, whereupon a vacuum is produced there. Only then can walls be opened without reducing the UHV too much. By pushing the rods labelled 1 and 2, the sample is transported in successive stages into the central chamber. Several instruments are attached to the chamber, including an XPS. On the right, an AFM can be discerned in the UHV chamber.

AH : How did the various instruments complement each other ?

HA : The spectrometers provided structural information. They give a chemical signature. One point of interest was silver on magnesium oxide. In order to have a simple model of glass we chose to study this problem within pure single crystal. We had the probe in situ in the same UHV chamber where we had the instruments to add the deposition techniques. In the case of silver it was just thermal evaporation. We wanted in situ real-time studies of the atoms arriving upon the substrate, the oxide surface. There were two models in this problem. One was that the atoms remain isolated or form small islands, so that the growth process is two-dimensional, so that you first get a perfect monolayer before a second layer is started upon. The other is that growth is three-dimensional with occasional collapses into flatness. To study this it is of course useful both to look directly and to use diffraction techniques. But in order to understand the process you need to grasp the interaction between the silver and the oxide. And only spectroscopic techniques will help here. We always tried to look at a problem from two differing points of view – in this case geometrical and chemical.

AH : You make it sound easy. You just use one tool and you get the topography, and then you use another and you get the chemical composition.

HA : Well of course it is not at all easy. It was very difficult because for instance, the STM works very well when you have a smooth surface but when you have corrugation it becomes much more difficult, because this corrugation interferes with the instrument. In spectroscopy you integrate over the size of the beam which is much larger than the surface scanned by the AFM. So you have to do many different experiments to see what effect the temperature has and so on. You also have to model the interaction. This was a little known problem. What is the mechanism of very small silver clusters on magnesium oxide with other silver clusters in the neighborhood ? It was a new problem. So it took time to understand the system.

AH : What is the measure of success ? It was partly CNRS, so you were under pressure to publish ?

HA : Yes.

AH : And since it was partly Saint-Gobain you had to get patents ?

HA : We had to do both. It was an interesting exercise in communication. In my position as head of the lab, I could not use the same words, the same way of presenting things when addressing different audiences. From time to time it was necessary to gather the scientific and the industrial people together under one roof.

AH : And what language did you speak then ?

HA : Fortunately everyone was happy with this lab, so it was not quite so difficult. The conditions were good. Nonetheless your question is quite correct. It was interesting.

AH : How did you convince Saint-Gobain that this would have a pay-off ? And how did you negotiate long- and short-term goals ?

HA : The short term was a problem. It was not straightforward to plan a new product for the company. The pay-off was very diffuse and difficult to identify. One way of motivating the directors was the argument that we trained very good PhD researchers for Saint-Gobain. And this was not expensive for Saint-Gobain, because they shared all the expenses with CNRS. Up until now this has not been a problem.

AH : Stanley Whittingham told me that in the last 15 years or so there has been a tremendous shift in company planning towards the short term in industry. Partly this was due to the MBA education and the fanning out of this new generation of business administrators into all nooks and crannies of industry. As a result the long-term disappeared, because everything had to fit into the financial year so that you have something to show to your shareholders.

HA : It is true that this has taken hold in industry. We had the good fortune that it was not very developed in Saint-Gobain. But also, the time required for the development of new glass materials just is acknowledged to be greater than that in electronics or informatics. When we start new projects, we are simply not able to show a product six months later. So we are less exposed than people in other fields, but the general development that you alluded to certainly has taken place. Maybe our situation will also change in the future. We may be excessive.

AH : Has the accountancy changed for you ? Did you have to write annual reports ? And has it changed over the last ten years ?

HA : In general ?

AH : Well, for the CNRS I can sort of imagine it. In academia you would specify the number of publications that you have produced and that is the measure. End of story. And that is very simple accountancy. But if you account to a company, keeping in mind the increasing influence of MBAs : did you have to account for your expenses in ever greater detail ?

HA : I do not think there has been such a change in the last decade.

AH : And do you write annual reports ?

HA : Bi-annual. But I am not in this lab anymore ; I left two years ago.

AH : Okay, so during the 1990s up until two years ago you wrote biannual reports to the company and in that period the structure of the reports did not change.

HA : That is correct.

AH : Did you have to specify just how much money you spent ?

HA : Yes, but also there, no change took place. And I always reported to the same person within Saint-Gobain. He was basically content with what we did, so it was never critical. It is true, it might have changed with a different person in charge.

AH : So, how did the instrumentation change throughout the 1990s ? The AFM became commercially available to an ever greater extent, you were able to buy many more things off the shelf. Is that true also of all the other instruments ?

HA : Yes, there are different aspects to your question. We used to build many instruments ourselves, and this was of great use for training. And this has changed. A reason the French PhD has been shortened is that equipment is being bought and not made in-house. That is a general trend. Science is changing as a result, because using a commercial instrument is not the same. When you develop an instrument yourself you know exactly how to get the result. In the specific case of AFM/STM : probably the AFM has been developed much more than the STM. In the STM the major breakthrough was with the driver and that was quite early. I think it was possible to purchase an STM driver already by 1992. Variable temperature was a little more difficult, but it was certainly available by 1994. Different ways of scanning and acquiring information were developed. Otherwise the evolution was purely technical : cheaper, and more diverse (such as an STM expressly for electrochemical research). By contrast the AFM has developed rapidly. Tapping mode and other modes where you measure not only the distance but also hardness, conductivity, adhesion, chemistry. It has become possible to map all these parameters. This explains why more and more people use the AFM.

AH : It has also become cheaper, right ?

HA : Yes.

AH : It has certainly become more user-friendly, adaptable to different circumstances.

HA : Yes. For the STM : there have very beautiful studies made of the coupling between tunneling and modulation. You might modulate the tunneling current with light for instance. You can even leverage the spin of the tunneling electrons. So you can do beautiful physics. But this contributes little to the democratization of the technique.

AH : I have the sense that Calvin Quate, by contrast, is working hard to increase throughput.

HA : Yes, that is right. There can be two reasons for doing that. To make the investigated part of the surface larger – of use in the semiconductor industry. And to shorten the time required for a scan. He is trying to use the system technologically.

AH : Okay. Two years ago you left your lab. Your own lab. Why ?

HA : I wanted to try something new and I was lucky to find someone who was well capable of taking over and for whom I have a lot of respect. He is from a different background. So now it is a different group. I became the Scientific Director of Saint-Gobain Recherche. There are two parts to the job ; one is to be the scientific manager, the other is to establish contacts in the outside world, and to promote innovations within the company, for instance with the marketing people.

AH : You were promoted ?

HA : Yes.

AH : And you have become slightly removed from lab work ?

HA : Yes, completely, I am now involved in organizational work.

AH : In fact, our project resembles your job in the sense that we stand back and look at the scientific research and try to gain a perspective ?

HA : Yes, you could say that.

Fin de l'enregistrement

Pour citer l'entretien :

« Entretien avec Hervé Arribart », par Arne Hessenbruch, 19 février, 29 mai et 20 février 2001, Sciences : histoire orale, /spip.php ?article47.

Pour citer l'entretien :

« Entretien avec Hervé Arribart », par Arne Hessenbruch, 19 février, 29 mai et 20 février 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article47.

Lieu : dans le salon (les 19 février et 29 mai 2001) et dans la petite salle de réunion (le 20 février 2001) du Dibner Institute, Etats-Unis.

Support : enregistrement sur cassette.

Transcription : Arne Hessenbruch.

Édition en ligne : Sophie Jourdin, Sacha Loeve.

DE GENNES Pierre-Gilles, 2002-05-02

Sophie Jourdin — 2011-06-15T20:52:04Z

Pierre-Gilles De Gennes (October 24, 1932, Paris – May 18, 2007, Orsay) was a French physicist and the Nobel Prize laureate in physics in 1991. He was Director of the École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI ParisTech) from 1976 to 2002.

He majored from the Ecole normale supérieure in 1955 and took his PhD in 1957. From 1955 to 1959, he was a research engineer at the Atomic Energy Commission (CEA) in Saclay, working on neutron scattering and magnetism. During 1959, he was post-doctoral visitor with C. Kittel at Berkeley. When he became assistant professor at Orsay in 1961, he started a group on superconductors and authored The Superconductivity of Metals and Alloys (W.A. Benjamin, New York, Amsterdam,1966). In 1968 De Gennes switched to liquid crystals and published The Physics of Liquid Crystals (1974). Meanwhile, he became a Professor at the Collège de France in 1971 and started a collaborative research on polymer physics with Strasbourg and Saclay. The joint project became known as STRASACOL (Strasbourg-Saclay-Collège de France). De Gennes' contributions to this domain are described in Scaling Concepts in Polymer Physics, published in 1979. Since 1976, De Gennes has been the Director of the École Supérieure de Physique et de Chimie Industrielles. In 1984, De Gennes turned his attention to interfacial problems, in particular in the dynamics of wetting. His research group – Françoise Brochard, Jean-François Joanny, Jean-Marc Di Meglio, D. Quéré – defined general laws of wetting and dewetting which are of great interest for practical applications. In 1989, De Gennes entered a new field, the physical chemistry of adhesives and became the champion of “soft-condensed matter physics”. In the late 1990s he started working on the design of artificial muscles with the Institut Curie. AT the time of the interview (2002), he was concerned with cellular adhesion.
De Gennes has received a number of honors and medals all over the world in addition to the Physics Nobel Prize in 1991 “for discovering that methods developed for studying order phenomena in simple systems can be generalized to more complex forms of matter, in particular to liquid crystals and polymers”. He is a member of the French Academy of Sciences, the French Academy of Technologies, the Dutch Academy of Arts and Sciences, the Royal Society, the American Academy of Arts and Sciences, and the National Academy of Sciences.

HERVE ARRIBART (HA) : Some articles published in the USA in 1991 presented you as a materials scientist. Do you consider yourself as such ?

PIERRE-GILLES DE GENNES (PGDG) : It depends on the period you are talking about. When we were in superconductors we did not consider ourselves as materials scientists. In fact we had a happy period when we could perform any amusing experiments, but when things became more complex we left. For instance, we had understood what vortices were doing in classical superconductors. Then there was a second stage where you should invent alloys which had special precipitates so that they would pin the vortices. That sort of action was beyond our technical means (we had very limited means in Orsay). So precisely at the moment the materials aspects became very important, we left. Clearly, with superconductors we were not in this game.
When we went to liquid crystals it was a little bit different. On the one side, there was great need of invention. Chemical invention was stimulated by the search for useful materials. In fact this case of liquid crystal was the first time I saw a molecule really built for a purpose. Bob Mayer, who was working with us in Orsay, had the beautiful idea that if you took a certain type of molecule which likes to make a tilted smectic phase, if you used a chiral molecule as a starting point, this tilted phase should be ferro-electric. And this idea came to him while queuing for lunch at the Orsay cafeteria ! He talked to us, then he came back and he induced some chemists – Patrick Keller and others – to construct a molecule like this. A few months later we had the first liquid ferro-electric. This I really look on as a landmark.

BERNADETTE BENSAUDE-VINCENT (BBV) : So would you define the materials approach as the design of molecules for a specific purpose ?

PGDG : Oui, I think that it is a clean description. There is a lot of wishful thinking where people claim that they do materials science. Often they construct objects and build molecules without knowing what to do with them.

HA : Working with chemists seems crucial for building molecules. Were there chemists in your Orsay group then at the Collège de France ?

PGDG : Yes we did have chemists in the Orsay group : Liébert, Strzelecki and Keller, three chemists. They did a lot, especially in polymerizing liquid crystals structures in order to get stable structures. They had their own lab. We had a cluster of seven laboratories on liquid crystals and they were one of the seven. At the Collège de France, when I came we had a very similar situation. For one, we had Jean Billard who was working in close cooperation with a chemist at the Collège. And Jean Jacques, who was a chemist – a great man who is dead now – took one of his best chemist coworkers – Maya Dvolastsky – and he asked her to go and work in my lab. In fact she worked for twenty years with my group.

HA : And during the superconductor period ?

PGDG : As I said during the superconductor period we were not materials inclined. We left the subject when it became materials science.

BBV : Do you think that it was the subject of liquid crystals that led you towards a materials approach or was it a more general trend in France in the late 1960s ?

PGDG : A little later when we became interested in polymers. We were stimulated by the notion that you could get some useful product. This was a time, after the 68 movement, when we began to feel that we need to be useful. For the liquid crystal project, it was intermediate. We had the notion that these materials had to be useful but we did not think that it was our duty to invent systems. We were interacting with people at Thomson who were very close – one mile from us. I had a great admiration for the Thomson research lab because they had been very active in laser research. They had a very clever advisor Pierre Aigrain, but the French activity in liquid crystals activity was not very brilliant. Looking at this time from a distance I think that had it been ten years later, we would have taken dozens of patents. At the time, the push towards application was not very strong. (I admit that we would never have invented this classical display that we have in our watches because to me it would have looked too complicated. I would have been afraid of producing the twisted system in industrial conditions. But who knows ?)
Then we went to polymers and many of us began to interact with industries. Around 1975, we really entered into an industrial network.

HA : Is there a continuity between superconductors, liquid crystals and polymers ?

PGDG : For the liquid crystals, I think we have been lucky. The Russian school had a glorious past. They could have done an immense amount of work but they did not go far enough because they had a prejudice against chemistry and dirty materials. Because of that we could set up a French activity on liquid crystals without having Russian competition. It was a great luck.

HA : However you were not an advocate of dirty science ?

PGDG : The tradition of superfluidity was very clean. The materials we were using were model materials with few defects. When Anderson used the word “dirty superconductors” he meant alloys. It is true that the physics of alloys has been very different for superconductors from the physics of pure metals. You can reduce the correlation length, you can control it by choosing the mean free path. There are many facets that become available when you accept to work with alloys. But in my mind, these alloys were perfect alloys without any precipitation or any complicated effect. They were ideal materials, although Anderson used the term dirty alloys (for provocative reasons).

BBV : Could you please clarify YOUR notion of dirty material ?

PGDG : I don't use it often because in many cases there is a prejudice. My own distinction would be slightly different. It would be between universal and zoological. Let's take a different field, like interfacial science : you can find universal features in this. You can construct general laws. The statics and dynamics of wetting are also pretty universal. But if you have a very specific problem such as making a polymer hydrophilic on its surface, then you enter into a certain amount of zoology. For instance, to create a hydrophilic surface by a plasma treatment, this plasma treatment works in an unknown fashion with empirically chosen gases, under conditions that are not deeply understood. Details on a chemical surface are not universal, and when you work for a practical purpose, you better go into these details. Our attitude as physicists was to start from the universal features… with the hope that it would be useful for applications later.

HA : This is a physicist's perspective. But when dealing with polymer materials you had to extract some cleanness out of dirty stuff.

PGDG : It is true that there is a huge conceptual gap between semiconductors where you look for impurity fractions which are amazingly small and polymer physics where in all cases you will synthesize a polymer by a process which has some randomness. However, you can build up universal laws despite the intrinsic distribution and complexity of these materials.

HA : What lead you to soft matter science ?

PGDG : There is an amusing historical aspect. We had been working on superconductors when one day we had a beautiful seminar by Charles Sadron, one of the founders of polymer science in France. He started from polyethylene (that we suck when we suck milk from a bottle) and moved to considerations on DNA. He covered everything, in this wonderful talk. Our little group in Orsay was fascinated by his talk and we decided to go that way. Sadron's lab (then directed by Henri Benoît) was brilliant not only in science but also from the human aspect : they accepted us coming with our questions sometimes relevant and often stupid. They really established a co-operation with us. We worked for two or three years on polymers (it was roughly in 1966). We produced some little theoretical reflections on the dynamics of chains in solutions. But we didn't have an experimental lab with us in Orsay. This situation of hanging on theory exclusively, I did not like it. In 1968 or ‘69, we heard about liquid crystals by Georges Durand. He came back from the US and told us it was something for the future. We listened to him. So we suddenly shifted from polymers to liquid crystals and we worked on it for about 5 years. It was a happy period because within a few months when we crystallized the idea we got seven independent units cooperating on this project. There were chemistry, as I mentioned, nuclear resonance, defects (Friedel was very helpful because there was a tradition), optics, theory, and crystallography. I may forget some of them but it came up to a bunch of six-seven groups working together in a happy way. Funding was easy. These groups were not nervous about their future ; they were very open and willing to go into something like that. It was a great time to connect all these good people and just working together. The results were obvious. Within two or three years there was a French science on liquid crystals. There had been one fifty years before with Georges Friedel. But there had been a gap with only one group flying the flag energetically, the Chatelain group in Montpellier. They were lonely, however. They had a good education in liquid crystals but many tools that were obvious to us - such as inelastic light scattering, or nuclear magnetic resonance - were unknown to them. So to come back to our point, we in Paris could set up something very efficiently in a short time and one of our sources of pride was that it cost no extra money to the taxpayer. Because all the equipment was already there, there was no new costs.

BBV : You mentioned that you took advantage of the large apparatus in Orsay…

PGDG : Not big. It was not synchotron or reactors, no large machines.

HA : And neutron scattering ?

PGDG : There was some neutron scattering on liquid crystals but it was minor. X rays yes ; we used a lot of x rays especially when we came to the more zoological work with a long list of smectic phases which are more and more complex. But no large apparatus.

HA : When you began on polymers was there a lot of experimental data from neutron scattering ?

PGDG : We came back to polymers after liquid crystals. I was at the Collège de France. We established a three-group collaboration with Strasbourg (Henri Benoît, a leading figure) and a group with Gérard Janninck at Saclay on neutron scattering. Here neutron scattering was very helpful to examine the conformation of one chain in a dense system where there are many other chains. If you have isotope labeling you can have this chain labeled, and you look at this chain and describe the conformation of one particular chain. In that case, there was an old prediction by Paul Flory that this chain would behave like an ideal random walk – which is surprising for a strongly interactive system. Indeed the Janninck group proved that this was the case. So we had this cooperation, we were what we call in French "la mouche du coche", a little fly stimulating the carriage but we had very little meat. Gradually however we got some. Francis Rondelez installed clever optical techniques. At the Collège at that time we had two types of activities : one was polymers, the other one being surfactants. It was the time when young group leaders became advisors in industries. Christiane Taupin, who worked on surfactants, went to Levallois to head a group of Atochem. Francis [Rondelez] was an advisor to Elf, and I was an advisor to Rhône-Poulenc. We worked more and more in close connection with industry. This was another happy time also based on cooperation. However it was a different cooperation, no longer a federation of little groups but a cooperation of large units, like Strasbourg. In Strasbourg they had a culture in light scattering and H. Benoît had constructed very detailed descriptions based on light scattering. Suddenly they were given the neutron scattering with isotopes providing information at a smaller scale (50 Ångströms instead of 5000). They were immensely happy with the neutron and Benoit wrote a book about neutrons and polymers.

HA : Nevertheless you spoke in critical words about big instruments.

PGDG : That was later. From the 1960s to 1985, I was a supporter of them because they had an educational aspect. This may be specific of European countries which have been delayed by the war. In the provinces, France had excellent abilities but no education. If you took young scientists from the lonely sites and brought them to Grenoble or to Saclay they learnt very fast in this intense research milieu using many concepts they had never heard about. They came back to their own labs and brought what they had learnt. So it was immensely useful. I think that the early generation of big machines has been excellent. At this moment, I am less enthusiastic because the educational problem has been solved, fortunately. A student in a small city in France can have a good education in basic physics of condensed matter. From the point of view of discovery, the density of discoveries around big machines has dropped down fast. Let me take an example. Going back to the far past, in 1957 (the year when the Russians launched Sputnik), at the first international conference that I attended as an engineer at the CEA in Stockholm. It was about neutron scattering. I learnt two things from this meeting : I heard a talk by Harry Palevsky, a student of Fermi. He was an invited guest for six months in Stockholm. He had worked on the very small Stockholm reactor using energy selection methods which are very primitive – it was just a beryllium filter : it does not provide a peak in energy, just a step. Using only that, he has been able to study the protons of helium. That was beautiful ! It taught me in some sense that you could work with simple means without big machines. The second thing I learnt was the danger of theoretical gurus. There was a number of them at this meeting, in particular Walter Marshall and Roger Elliott from England. I was just a PhD student. I came and said to Roger Elliott that he wrote something wrong in a review article. He pushed me out although he was wrong. That taught me some caution with the old gurus.

HA : Let us come back to adhesion. It was a good example of a dirty problem at that time based on some science and on empirical rules.

PGDG : You are absolutely right. We entered into adhesion after spending some time on wetting, which is more fundamental. I was struck by the great chemical successes achieved in adhesion. The example that I often quote is anaerobic adhesives. These are systems that you want to reticulate, to polymerize once they are in a proper position between two walls but you don't want them to react stupidly in other situations. In that case, chemists were able to have a polymerization induced only in the presence of certain metal surfaces like copper. That is chemical invention. My impression is that chemistry has been the leader in this field. We physicists, and the people from mechanics, we were in a more modest position. People from mechanics brought measurements. To define adhesion properly instead of measuring the force between two pieces, Griffith and others established that you have to measure the separation energy per unit area. So people from mechanics provided 1) measurement techniques like the cantilever technique and 2) new concepts. Thus, chemistry ranks one, mechanics two, and physics comes only as number three.
So in adhesion meetings you could hear these nice theoretical talks – not easy theory indeed – but very nice. At the end of such talks somebody raised his hand and asked : “what does it tell me about this particular adhesive where I found that when I modify my molecule by putting this methyl group in the sixth position I get a much better adhesion than if I put it in the fourth position ?” So that was a kind of Babel Tower. Our modest aim was to try to build up a common language. We helped a little bit in two respects. One is the question of very soft adhesive materials where dissipation inside the adhesive is what makes a material good. We could help because it was close to concepts we had met in polymer science. The other question concerns little polymer chains that intertwine. Liliane Léger has been working on it. We thus had, let's say, two years full contribution but it was very modest. It did not clarify the science of adhesion. But it helped create a number of teams in France. If you look at the situation I would say we have :

1) a classical lab in Mulhouse where modern physics was introduced by Günther Reiter ;

2) Costantino Creton here in PC [the École Supérieure de Physique et de Chimie Industrielles] ;

3) Liliane Léger on polymer systems at the Collège de France ;

4) a small group with M. Shanahan in Corbeil.

HA : Apparently it took time for you to convince them to work on such a subject.

PGDG : Absolutely right. My dream would have been to set up a sort of adhesion science center in the Paris area. Ultimately I did not manage to do it. There are various scattered researches but no unity although it is not too bad.

BBV : Did you work on adhesion because you had industrial contracts or was it your own initiative ?

PGDG : I think it was our own initiative, although I may be wrong because it is very difficult to trace the origin of a project. We had no program with 3M, the great master in industrial adhesion. Rhône-Poulenc had some related problems but they don't sell adhesives as such. Latex is special : it is not a real adhesive. We heard about adhesives but it was not something important for them.

HA : And Gilbert Schorsch from Rhône-Poulenc ?

PGDG : He was more concerned with new materials, organo-mineral materials. Later they turned to adhesives. I don't remember well. I think that the wetting problem, dealing with interfaces led us to move to strongly interacting systems. But we should be very modest. Take for instance a standard adhesive material like the epoxy-glue that you buy in a supermarket. Frankly, I don't understand the way it works.
We are still working on adhesives. If you look at this blackboard here (Figure 1) you'll see that recently we have been concerned with cellular adhesion. We have a professor in medicine in Marseilles, Pierre Bongrand, a former student in a solid-state graduate school here in Paris, who brought a number of key measurements in adhesion.

Figure 1. Cellular adhesion schema

The notion is of a cell with a few sticky molecules at its surface but they are very small, very dilute. When the cell comes in front of another one, all the sticky molecules move to the contact region and build up bridges there. Ten years ago Bongrand and others understood the statics of that process and what the separation energy is. It is not at all what stupid people like me would have believed. When you begin to separate you do not have to cut a bond because all the stickers just go to a smaller surface but they don't disrupt their bonds. So the adhesion energy is just fighting against the osmotic pressure. People like these established deep ideas about the statics. While I had to give a course I realized that there was a cascade of problems concerning the dynamics and I started thinking about them. So we are still on adhesion.

HA : How do you see the links between biology and materials research ?

PGDG : I have been very critical about biophysics. For instance, physicists had in mind that they could do a lot of biophysics on cellular adhesive molecules by establishing the 3-dimensional structure of these proteins. It is helpful. However, it is not a very exciting program because the biologists are so clever that they immediately sequenced these proteins. They realized some parentages between the sequences, grouped them into families and could identify the function of the various pieces without a big instrument of physics. The interesting problems – how does it work in a tumor situation, or how do I influence this process, how do I stimulate them – are not in biophysics. Biophysics is doing only the details, not addressing the big question. That is why I have been so critical of this community who jumped into biophysics at one stage. Fortunately, I was partly wrong. There are good examples around here : at the Institut Curie Center with Jacques Prost, they really have a wonderful activity. For instance, they have a universal theory of molecular motors. That is a real success of biophysics. There are facets of biophysics that I respect very much but there are still old facets that I would call more engineering than science.

HA : Let's talk about the artificial muscle.

PGDG : The subject was started by a giant in polymer science, Katchalski. Polymer physics started with Kuhn in the 1940s. Ten years later Katchalski, a former student of Kuhn, said : “if we understand rubber, maybe we can devise a rubber or a gel where a chemical agent changes properties, transforming chemical energy into mechanical energy”. That was a beautiful idea. Katchalski did very sophisticated work with very simple means. He had very few materials available in Israel at the time : he used methylacrylate recuperated from the cockpit of World War II aircrafts. He did a wonderful job. The materials he produced demonstrated the principles but they could not have any practical application because of slow response and fatigue problems. This historical contribution raised an interesting challenge.
We started as a small thing. With gels, the response time was very bad. Then we tried liquid crystals systems with no solvent. You just changed the temperature to switch the conformation. That was tempting. So we have a project at the Institut Curie which requires delicate chemical synthesis. Another project was launched by a Japanese team in Osaka. They are electrochemists and they used a membrane made of a popular material for other purposes in large-scale electrochemistry. This membrane is called a Nafion ; with this Nafion they were able to achieve systems that under moderate voltage – a few volts – distort and then command actions. The response time was around one second. I am full of admiration : not only did they build up the material with the correct (large-area) electrodes but they also understood the dynamics of the process. The field is very attractive (but our contribution is very, very small).

HA : Would you say that artificial muscle is a bio-inspired material ?

PGDG : It is not really bio-inspired. It is based on polymer science and has nothing to do with an actual muscle. But I am fully convinced that bio-inspired materials will become more and more important. I was very impressed by the German team that found what are the peptides at work in making the shell of diatoms. Using this sort of results in the future is very tempting.

BBV : Did teaching play a part in your continuous shifts from one project to another one ?

PGDG : Ah oui, teaching played an important role. This figure on the blackboard on cellular adhesion really came from the fact that Françoise Brochard was having a course on soft adhesives for industrial people. When she asked me to talk about cellular adhesion I just realized that I could not teach it because I did not really understand the process involved. So it was an excellent push. Teaching is very helpful for theorists because we are often trapped in formal models. Mathematical writing does not give any idea of the real thing. We have to re-digest and transform the mathematical statements into a few simple sketches without any calculation. Teaching is good for going in this direction.

HA : What about your experience as a Director of an engineering school ?

PGDG : I have tried to keep scientific contact with the labs, on gels, on separation techniques and some other cases. I try to keep this place aware of new fields and to keep good contacts with local people. I sometimes missed the point because of too many duties, but right now I am very happy. We have new young professors such as Jérome Bibette working on emulsions, Ludwig Leibler on polymers, Jérome Lesueur on transport in superconductors and it is very stimulating to talk with them. The person you really want to direct such a place is somebody who is able to talk to everyone. I would be scared to have separate departments for physics, chemistry and biology.

BBV : Do you think that throughout your career you crossed disciplinary boundaries, or are you still a physicist but able to talk to other disciplines ?

PGDG : I tend to see it more as a process of learning. For instance when we entered the field of polymers we were like students. As I said, we made many mistakes. Our lives have been a cascade of student lives. At least this has been my feeling. For the theorists it is easier to move, they can switch more easily than experimentalists. But some experimentalists did switch : Etienne Guyon for example moved from superconductors to liquid crystals and granular matter. He is an interesting case.

HA : Do you intend to pursue your recent interest in glass ?

PGDG : The literature is difficult to grasp. We look at a certain sector, mainly on structural glasses, with problems in real space, numerical local space features.

Fin de l'enregistrement

Pour citer l'entretien :

« Entretien avec Pierre-Gilles De Gennes », par Bernadette Bensaude-Vincent et Hervé Arribart, 2 mai 2002, Sciences : histoire orale, /spip.php ?article59.

Pour citer l'entretien :

« Entretien avec Pierre-Gilles De Gennes », par Bernadette Bensaude-Vincent et Hervé Arribart, 2 mai 2002, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article59.

Lieu : bureau de Pierre-Gilles De Gennes, Ecole Supérieure de Physique et de Chimie industrielles, Paris, France.

Support : enregistrement sur cassette.

Transcription : Bernadette Bensaude-Vincent, Hervé ARRIBART.

Édition en ligne : Sophie Jourdin, Sacha Loeve.

GOODENOUGH John B., 2001-05

2010-02-04T14:39:22Z

John Goodenough, né en 1922 à Iena (Allemagne), est professeur et détient la Virginia H. Cockrell Centennial Chair in Engineering de l'University of Texas, Austin. Jeune homme, il s'est porté volontaire pour servir dans l'armée US comme météorologiste au cours de la Seconde Guerre mondiale. Après la guerre, il a étudié la physique à Northwestern University (près de Chicago) puis a travaillé au Lincoln Laboratory du MIT (Boston, Mass.) et dirigé l'Inorganic Chemistry Laboratory à Oxford University (Angleterre). Ses recherches portent sur les propriétés électroniques et ioniques des oxydes métalliques à la croisée de nombreux champs de recherche. Il a reçu le Von Hippel Award de la Material Research Society (MRS) en 1989 pour sa contribution à l'étude des solides où il s'est illustré par ses aptitudes à constamment lier les concepts de base de la physique et de la chimie à un large éventail de sujets théoriques. Goodenough est aussi reconnu comme l'un des scientifiques les plus influents des solid state ionics, champ de recherche sur les électrolytes solides.

BERNADETTE BENSAUDE-VINCENT (BBV) : So where did you start ? You graduated in chemistry, no ?

JOHN B. GOODENOUGH (JG) : No, not at all. Before World War II, I studied classics and mathematics. I took an introductory course in chemistry my freshman year at Yale as my science requirement for a Liberal Arts degree, but I had no thought of a career in science.

I had been awakened intellectually and spiritually while reading poetry at Groton School and trying to understand the metaphors of the Bible and the Church. Therefore, at Yale I was a young man in search of a calling for my life, so I read considerable philosophy. I became intrigued by the philosophy of science, and as I was reading Whitehead's Science and the Modern World, I came to the conclusion that, if I were ever to come back from the war and if I were to have the opportunity to go back to graduate school, I should study physics.

As an Army Air Force meteorologist, I dispatched tactical aircraft across the Atlantic Ocean during World War II. In 1946, while I was still stationed on the tiny island of Terceira in the Azores awaiting my turn to go home, a telegram arrived telling me to report back to Washington in 48 hours. In Washington, they sent me to Chicago where I was to have a choice to study physics or mathematics at either the University of Chicago or Northwestern University. My old Yale mathematics professor, Egbert Miles, had not forgotten me ! Confronted with this opportunity, I had a flashback to the evening I sat reading Whitehead before the military interruption. It seemed to me that "This is what I am supposed to do !" The next day I went to the University of Chicago to register for graduate studies in physics. When I arrived, the registration officer, Professor Simpson, said to me, " I don't understand you veterans. Don't you know that anyone who has ever done anything interesting in physics had already done it by the time he was your age ; and you want to begin ?"

BBV :It was really encouraging.

JG : Well, it didn't bother me at the time. I was simply grateful that, though still in the Army, my transition back to civilian life was so smooth. I left the Army in 1948 and continued my studies with the G. I. Bill of Rights. When I completed the 32-hour qualifying examination, I decided I did not want to go into nuclear physics, so I signed up to do my dissertation in solid-state physics with Professor Clarence Zener. When I finished my Ph.D. thesis, I had two job offers : one was to be an assistant professor at the University of Pennsylvania and the other was to join the Lincoln Laboratory of the Massachusetts Institute of Technology (MIT). I chose the latter.

ARNE HESSENBRUCH (AH) : What year was that ?

JG : That was 1952. Lincoln Laboratory had been established by the Air Force to develop the Semi-Automatic Ground Environment (SAGE) system for air defense. The system integrated radar, communications. and the digital computer. At that time the digital computer didn't have any memory other than a 16 x 16 bit electrostatic storage tube. Jay Forrester, an electrical engineer, had invented the coincident-current magnetic-core memory. This memory uses a magnetic torroid (core) with a square B-H hysteresis loop for each bit of stored information. Forrester had noted that the magnetic alloys Deltamax and Permalloy had the required square B-H hysteresis loops, and he had used them to prove the concept of his memory. However, the switching speeds were too slow. As an electrical engineer, he assumed the problem was eddy-current damping in his metallic cores, so he had ordered tape cores that were rolled to thicknesses as small as 1/8 mil. But the switching speed was still an order of magnitude too slow. Therefore, he had decided to investigate ferrimagnetic oxides that were insulators. My assignment was to help design a ferrimagnetic oxospinel that had a square B-H hysteresis loop. Those in Europe who had developed the ferrimagnetic spinels did not attempt to do this as they were convinced it was theoretically impossible. The problem was that you cannot role a brittle oxide as you can a metallic alloy in order to align the easy-magnetization axes of all the individual grains of a polycrystalline core, which is how the square B-H hysteresis loops are obtained in Deltamax and Permalloy.

The first thing I did was to analyze what controls the shape of a B-H hysteresis loop. I calculated where the domains of reverse magnetization are nucleated and what hinders their growth in a magnetic field. My calculations showed that if the crystallographic axes of easy magnetization are not well-aligned across a grain boundary, magnetic poles at the boundary may induce nucleation of reverse domains even where the applied magnetizing field is opposed to the magnetization in these domains. However, because the magnetization of a ferrimagnet is much smaller than that of a ferromagnet, nucleation of the reverse domains does not occur in a ferrospinel even where the easy-magnetization axes are misaligned until the magnetization is in the direction of the reverse-domain magnetization. This result meant that it was theoretically possible to obtain a square B-H hysteresis loop in a ferrimagnetic ceramic with unaligned grains provided some other defect could be introduced that would not only nucleate reverse domains at a desired reverse field, but would also release them, once nucleated, to grow until they reversed the magnetization. This was an important finding.

I also analyzed the factors that controlled the switching speed of a magnetic core. It was immediately apparent that the driving field to switch a core was restricted in the memory application to a magnetic field strength H = (H - Hc) < Hc where Hc is the threshold field to switch the magnetization direction. The coercive field Hc in the Permalloy tapes was too small to allow the driving force needed for fast switching. Moreover, the analysis showed that there is an intrinsic damping of spin rotations that would still be present in the absence of eddy currents. It was therefore clear that a somewhat larger coercive field Hc than that of Permalloy was needed, and the remaining problem was to discover the appropriate imperfection that should be introduced to provide many centers for nucleating domains of reverse magnetization at an acceptably large H » Hc.

Meanwhile, my colleagues were empirically mapping the MnO-MgO-Fe2O3 phase field to determine the compositional range of the ferrimagnetic spinels and the influence of annealing temperatures on the shape of the B-H hysteresis loop. It was in this phase field that promising hysteresis loops had been published. We found a certain compositional range rich in manganese in which the spinels were tetragonal rather than cubic. Previous workers had assumed that the tetragonal distortion was due to the disproportionation reaction 2 Mn(III) = Mn(II) + Mn(IV) since this reaction had been observed at the surface of Mn(III) oxides in acidic solution. However, I had read Pauling's The Nature of the Chemical Bond, which helped me to observe that the Mn(III) ion had an orbital degeneracy in a cubic octahedral site that would be removed by a distortion of the site to tetragonal symmetry. I therefore reasoned that at a critical Mn(III) concentration, there would be a cooperative orbital ordering that minimized the elastic energy and that the tetragonal distortion we observed was due to such a cooperative orbital ordering. Unknown to me at the time, Jahn and Teller had pointed out some years earlier that a molecule with an orbital degeneracy would distort so as to lower its energy, but my deduction was the first realization that, in a solid, cooperative orbital ordering to minimize the elastic energy would induce a crystallographic distortion below a transition temperature Tt. This effect is now known as a cooperative Jahn-Teller distortion. At higher temperatures and lower concentrations, the individual site distortions would be disordered and would fluctuate in what is known as a dynamic Jahn-Teller distortion. We also noted that we could obtain square B-H hysteresis loops in compositions that were cubic, but close to those that became tetragonal below a Tt, if the cores were annealed for a specific period at a precise temperature. In this way the technical problem was solved empirically ; the coincident-current magnetic memory proved to be a critical step in the development of the digital computer. However, I didn't know until some time later how the annealing procedure introduced defects that nucleated domains of reverse magnetization.

AH : When did you find this out ?

JG : The Russians were interested in our development of a computer memory. Therefore, I was invited to Sverdlovsk (now Katerinaberg) in 1961 to talk about our work. While there, Shur showed me evidence that the domains of reverse magnetization were nucleated within the grains and not at grain boundaries. In a 1964 experiment concerned with Li+-ion ordering on the octahedral sites of the spinel structure, I observed that the Li+ ions ordered with all trivalent counter cations except Mn(III). I then realized that annealing the memory cores for a specified period at a precise temperature was creating Mn(III)-rich chemical inhomogeneities within the cubic structure in order to reduce, through cooperativity, the elastic energy associated with dynamic Jahn-Teller fluctuations. These chemical inhomogeneities created magnetic poles within grains that were acting as the nucleation centers for reverse-magnetization domains in the memory cores.

BBV : So this is how you came to study oxides ?

JG : Yes. But let me tell you of one other deduction I made at that time that proved critical for my future studies. Néel had understood that the interactions between localized atomic moments may be antiferromagnetic as well as ferromagnetic. An open question at that time was the origin of the magnetic interactions and what determined their sign. Following a suggestion by Kramers, Phil Anderson had formulated the antiferromagnetic superexchange interaction in his Ph.D. thesis with Van Vleck. At the same time, neutron diffraction was developed as an experimental tool with which to measure directly the magnitudes of the atomic moments and their order below a long-range magnetic-ordering temperature. Wollan and Koehler had determined that the magnetic order in the antiferromagnetic perovskite LaMnO3 consisted of ferromagnetic (001) planes coupled antiparallel to one another along the c-axis (Figure 1 below). In La0.5Ca0.5MnO3, the magnetic order within the (001) planes consisted of both ferromagnetic and antiferromagnetic interactions. This anisotropic character of the sign of the (180o - f) Mn-O-Mn interactions in the pseudocubic MnO3 array was a mystery that delayed publication. I realized that the anisotropy must reflect a cooperative orbital ordering at the Mn(III) ions. As I had already worked out in my mind rules for the sign of the superexchange interactions that depended on the occupancies of the interacting orbitals, it was possible to predict the cooperative orbital ordering in LaMnO3 and the charge and orbital ordering in La0.5Ca0.5MnO3 so as to account for the magnetic order. We published back-to-back papers in the Physical Review. Kanamori subsequently provided a more mathematical formulation for the superexchange interactions, and the rules I formulated then are known as the Goodenough-Kanamori rules for the sign of a superexchange interaction. With these rules it has been possible to understand a variety of complex magnetic orderings in magnetic materials. Moreover, these studies led me to an investigation of the change from localized-electron configurations coupled by relatively weak interatomic superexchange interactions to itinerant electrons where the interatomic interactions become stronger than the intraatomic interactions. They also made me realize that, as a physicist, I could play a scientific role building a bridge between the engineer needing a material to realize a device and the chemist charged with the problem of designing a material that would perform the engineering function.

Figure 1. Perovskite structure

AH : And this realization came to you in the mid 1950's ?

JG : Yes, but its evolution was a bit more complex. When we had completed our project with the memory cores and working memories were being realized, Jay Forrester called us to his office. We expected to get a pat on the back, maybe a promotion. Although he spent 30 seconds congratulating us on a job well done, he had another purpose. "Now that you have worked yourselves out of a job, what are you planning to do ?" he asked.

AH : What an interesting managerial technique.

JG : Half the group decided to take the technology to industry ; I decided to stay and spent the next weekend figuring out what I should do next. I came up with the idea of a magnetic-film memory that would switch by a simultaneous rather than a sequential rotation of spins.

AH : Do you remember when that was ? Do you remember the year ?

JG : I believe it was 1956 or 1957.

BBV : So you stayed at the MIT Lincoln Laboratory for that ?

JG : Yes. I was put in charge of this new project as well as of the old ceramics laboratory. Since several people had left, I was permitted to hire a few new people. One of those I hired turned to me about a year later and said, "I want to become famous ; let me take charge of the magnetic-film project." He was an experimentalist, so I said, "All right, you can have it !" I gave my full attention to what was left of our ceramics laboratory. It turned out that the magnetic-film memory only filled a small niche in the market. It proved a difficult technology, and other developments came along that were more competitive. It appeared to be a good idea at the time, but it didn't become a winner. However, my decision to give the magnetic-film project to others made me concentrate on solid-state chemistry and gave me about 12 years in which I did some fundamental studies and wrote two books.

BBV : Which one : Metallic Oxides ?

JG : I wrote first Magnetism and the Chemical Bond. I realized I could tell a great deal about the nature of the chemical bond from the magnetic order and the crystallographic distortions because I knew how the signs of the interatomic exchange interactions depend on the number of electrons in the interacting orbitals and how cooperative orbital ordering would optimize the exchange interactions. In those days many people were interested in investigating the complex magnetic orderings revealed by neutron diffraction and in interpreting the origins of these complex orderings. For example, I was able in 1961 to show that where the Jahn-Teller distortions are fluctuating, the (180o-f) Mn(III)-O-Mn(III) interactions in a perovskite became isotropic, ferromagnetic vibronic superexchange interactions. Vibronic superexchange interactions are now returning as a subject of interest ; and we have recently shown they play an important role in the manganese oxides that exhibit a colossal magnetoresistance. Moreover, Tom Kaplan of my group was calculating the ground-state magnetic order where there were competitive interactions that gave rise to spiral-spin configurations, configurations that were quite complex in spinels where a spiral-spin configuration was superimposed on a Yaffet-Kittel triangular-spin configuration. I extrapolated the rules for the superexchange interactions to the case of itinerant-electron magnetism, reasoning that it was the perturbation expansion of the mathematical description and not the physics that broke down at the crossover from localized-electron to itinerant-electron magnetic interactions. In that book, my primary interest was in the variety of magnetic orderings that were observed in the d-block transition-metal alloys and compounds.

My book Les oxydes des métaux de transition is a French translation of a long review article entitled "Metallic Oxides". This review was an extension of my former book ; it concentrates on the transition from localized to itinerant electronic behavior. Localized-electron behavior occurs where the intraatomic interactions are stronger than the interatomic metal-metal or metal-anion-metal interactions, which is why the interatomic interactions between localized-electron configurations can be treated in second-order perturbation theory. The conventional one-electron band theory of itinerant electrons applies where the interatomic interactions are much stronger than the intraatomic electron-electron interactions. While I was still a graduate student, Mott had called attention to the fact that NiO should be a metal rather than an antiferromagnetic insulator according to the band theory. It is necessary to introduce into this theory the on-site electron-electron interactions to account for the localized-electron configuration of NiO. Hubbard presented the Hamiltonian that introduced this term, and the transition from antiferromagnetic insulator to Pauli paramagnetic metal where a band is half-filled is called the Mott-Hubbard transition. I realized that in oxides the metal-oxygen interactions open a large energy gap between the bonding and antibonding states of the valence s and p electrons ; d-electron redox energies may be found within this energy gap. Moreover, isostructural oxides were known of which some members were metallic and others were antiferromagnetic insulators. For example, TiO is a metal whereas MnO is an antiferromagnetic insulator ; SrVO3 is a metal whereas LaVO3 is an antiferromagnetic insulator. These observations meant that I should be able not only to determine the number of electrons in a d-electron bond from the sign of the spin-spin interaction across it but also to study the transition from localized to itinerant electronic behavior in d-block transition-metal oxides without the interference from overlapping broad bands that occurs in the magnetic alloys. However, our experiments designed to monitor this transition were frustrated at that time by lattice instabilities that gave rise to either phase separation or the appearance of a charge-density/spin-density wave (CSW/SDW). Before we could unravel why this was so, Senator Mansfield passed an amendment that forbade federally supported facilities like Lincoln Laboratory from engaging in fundamental research not targeted on a specific engineering application. So, I was told I could no longer continue my fundamental studies.

AH & BBV : When was this ?

JG : It was about 1970. So I had had about 12 years from 1958 to 1970 to do fundamental research.

AH : Was all of this done at Lincoln Laboratory ? Were you involved in the organization of the Department of Materials Science and Engineering at MIT ?

JG : Yes, the work was done at Lincoln Laboratory. No, I was not involved with the MIT-campus bid to establish an NSF-sponsored Materials Science Institute.

To return to my story, when I was told I couldn't continue untargeted fundamental research, I was forced to think through what I and my group should do next. It was the early 1970's, and the first energy crisis had arrived. People were lined up at the gas stations. So it seemed obvious that I should consider doing something related to energy.

AH : But there is a gap of more than a year because the energy crisis was in 1973.

JG : Yes, there was a gap during which time I developed a sole for a travelling-wave amplifier ; we made a MgO-Au composite that improved the secondary-electron emission by over a factor of 100. But the project manager who requested this development became preoccupied with a big radar sink for money, so the development was never exploited.

In the same period, researchers at the Ford Motor Co. had discovered fast Na+-ion conduction in a ceramic, sodium-beta-alumina. They proposed using it as the electrolyte and separator of a Na-S battery that used molten sodium as the anode and a molten sulfur compound as the cathode. It would operate at 300o C. I was asked by the DOE to be on the evaluation panel of this project. It was my introduction to solid alkali-ion electrolytes and to batteries. I was subsequently invited to Stanford University for two days to give a seminar on my work on the electronic properties of oxides with the perovskite structure and to interact with various solid-state research groups there. Each professor had his own fiefdom, and one of those was under Bob Huggins who asked me, "How would you design a Na+-ion electrolyte ?" Since perovskite-related materials were on my mind, I replied, "I would choose a host framework that contained tunnels as occurs in the hexagonal sodium-tungsten bronze, but I would choose structures in which the tunnels run in more than one direction and intersect one another. I would also choose a main-group element rather than a transition-metal atom as the framework cation to obtain a solid electrolyte, i.e. a framework that is not an electronic conductor." As I was flying back to Boston, it occurred to me that sodium-beta-alumina was a framework structure in which the mobile Na+ ions move in planes containing intersecting tunnels. I was interested to learn that, subsequent to my visit, Huggins and his post-doc Stan Whittingham used hexagonal tungsten bronze as a sodium-insertion electrolyte for measuring Na+-ion electrolytes. Meanwhile, I had decided to investigate Na+-ion conductivity in framework structures having tunnels running in three dimensions as I reasoned that a ceramic with three-dimensional Na+-ion conductivity would be superior to one with only two-dimensional Na+-ion conductivity. I embarked on this study before I turned to the problem of clean energy.

An analysis of the energy problem showed that there were only four alternatives to fossil fuels as energy sources : hydropower, geothermal, solar (including wind), and nuclear energy. Hydropower was already being exploited and geothermal energy is geographically limited. I didn't want to consider nuclear energy, so I analyzed the solar-energy problem.

AH : Why didn't you want to do nuclear ?

JG : I wasn't a nuclear scientist and we weren't a nuclear laboratory, so it wasn't appropriate for us. Similarly, wind energy was not matched to my interests. It would have been appropriate for us to work on photovoltaic cells, but others with more experience of broad-band semiconductors were doing photovoltaic development, so I began with wavelength-selective films for passive thermal heating. We developed some of these, but I soon realized that long-term energy storage was a key to harnessing solar energy. Since energy is most versatily stored long-term as chemical energy, I had the idea to generate hydrogen from water by photoelectrolysis. I soon discovered that Fujishima and Honda had already discovered this effect on TiO2 I also proposed the use of yttria stabilized zirconia for the electrolyte of a solid oxide fuel cell to be operated with the waste heat of a conventional power plant. As a third leg, I proposed continuing work on Na+-ion solid electrolytes for the Na-S battery. In that effort, I identified several framework structures (I called them skeleton structures) that supported three-dimensional, fast Na+-ion conductivity. One of these was Na1+3xZr2(P1-xSixO4)3, which has the hexagonal Fe2(SO4)3 framework. My colleagues named it NASICON, standing for NA SuperIonic CONductor, just as I was leaving Lincoln Laboratory.

AH & BBV : Who chose that name ? What was the name of your colleague who coined the word NASICON ?

JG : There were two I think : Alan Strauss and Kirby Dwight. When I requested funding to work on these energy products, the bureaucrats in Washington said, "The National Atomic Energy Laboratories are in trouble because atomic energy has gone out of favor. Therefore, the DOE will only support energy programs in these laboratories. Lincoln Laboratory is an Air Force laboratory and should involve itself with problems directly related to the Air Force." Therefore I decided that I should leave the MIT Lincoln Laboratory.

I had always wanted to help the third-world countries, and solar energy was a program that would be well suited to some of the countries newly enriched by the increase in oil prices. Therefore, when I was approached by an Iranian about the possibility of heading up a research institute in that country, I decided to explore the idea. I went to Tehran and raised $7 M from the Shah for an institute to be associated with the Aryamehr University there.

AH : When was this ?

JG : 1974 and 1975. While contemplating back in Boston whether to make such a move, a letter from Oxford University, England, arrived asking me to put my name in nomination for Professor and Head of the Inorganic Chemistry Laboratory. My wife did not hesitate to recommend that I put my name in nomination, and I thought, "If the people at Oxford have that much imagination, then perhaps that is what I should do." I was duly elected, and in 1976 I took up the post in Oxford.

BBV : So you abandoned your Iranian project ?

JG : I did.

BBV : And the $7 M ?

JG : Yes. As it turned out, within two years the Shah was ousted, the American Embassy was taken hostage, and the Institute I had helped establish was abandoned. My election as Professor and Head of the Inorganic Chemistry Laboratory at Oxford was quite extraordinary as I had had only one course in Qualitative Chemistry as a Yale freshman in 1940 and one in Organic Chemistry in 1948 at the University of Chicago. I came into Chemistry by the back door working with solid-state chemists trying to build a bridge between them and the engineer and using their expertise to design experiments to explore fundamental physics questions in solid-state science.

AH : Is that what the Oxford Inorganic Chemistry Laboratory was interested in ?

JG : The Oxford Inorganic Chemistry Laboratory included preparative organometallic chemistry, chemical crystallography, bioinorganic chemistry, thermodynamics, electrochemistry, and several spectroscopic groups as well as solid-state chemistry. My predecessor, Professor Stuart Anderson, was a solid-state chemist, and there was a preference to maintain continuity in that field. As I had been working with solid-state chemists, I presume the Dons thought I would bring a solid-state program that complemented other on-going activities there.

Initially, I decided to investigate the chemistry of the photoelectrolysis of water on oxide surfaces and to extend my studies of ionic transport in solids to include proton conduction in oxide-particle hydrates and insertion compounds for cathodes of rechargeable lithium batteries. These topics introduced me to electrochemistry as well as to catalysis, and I later undertook studies of methanol oxidation at the anode of a direct methanol-air fuel cell, of the oxygen-reduction reaction at fuel-cell cathodes, and the mechanistics of a partial-oxidation reaction on phosphopolymolybdates. The study having a large commercial impact was the development of a cathode for the lithium-ion rechargeable batteries that have enabled realization of the cellular telephone and laptop computers, for example.

In the early 1970's, Ted Geballe and his student Fred Gamble were investigating at Stanford the insertion of various chemical species between the layers of the metallic sulfide TiS2 in order to demonstrate the existence of two-dimensional superconductivity. Michel Armand, then a student with Bob Huggins, was interested in the possibility of reversible alkali-ion insertion in TiS2 for use as a battery electrode ; Stan Whittingham of Huggins' group had used hexagonal tungsten bronze, a one-dimensional Na+-ion conductor, as an electrode, and TiS2 offered two-dimensional conductivity. Brian Steele of Imperial College, London, suggested at a meeting (proceedings edited by Van Gool) the use of TiS2 as the cathode of a lithium battery. At that time, about 1973, the energy crisis had stimulated the EXXON corporation to expand into an energy company ; Stan Whittingham and Fred Gamble were hired to initiate an energy program. Before I left for Oxford in 1976, Stan Whittingham published a paper in Nature showing that lithium can be inserted rapidly and reversibly into TiS2 over the entire solid-solution range LixTiS2, 0 < x < 1, and that the compound gives a fairly flat open-circuit voltage versus a Lithium anode of about 2 V. This publication generated extensive interest, and EXXON committed considerable resources to the commercialization of a Li/LiClO4/TiS2 battery. However, a passivation layer at the anode resulted in lithium dendrite formation on recharge. After a few cycles, the dendrites grew across the explosive LiClO4 liquid electrolyte, shorting out the cell and blowing up the laboratory. Safety concerns eventually led EXXON to abandon the project and, subsequently, its expansion as an energy company.

As a consultant for the DOE on the Na/S battery, I had become increasingly aware of these developments. It became clear to me that to avoid these safety problems, it would be necessary to develop an anode that was an insertion compound. However, such an anode would lower the voltage of the cell. I considered the origin of the metallic conductivity of TiS2 and understood that it would be necessary to insert lithium into a metallic oxide if a larger cell voltage was to be obtained. However, unlike the sulfides, there are few layered oxides. On the other hand, there are several LiMO2 compounds having a transition-metal atom M that have layered structures analogous to that of LiTiS2, so I decided to investigate how many Li atoms can be removed before the oxide structure becomes unstable. Extraction of lithium meant operating on the M(IV)/M(III) redox couple. To obtain a large cell voltage, I wanted a cation for which the energy of the M(IV)/Mn(III) redox couple was unusually low ; and to prevent migration of M cations into the depleted lithium layer, I wanted both the M(IV) and M(III) species to have a strong octahedral-site preference since migration was through a tetrahedral site. Therefore, I chose chromium, cobalt, and nickel as possible M atoms. At that time, Koichi Mizushima was visiting me from the University of Tokyo, so I asked him to perform the experiments. We were delighted to find that we could take out most of the lithium from the cobalt and nickel oxides without migration of these cations to the depleted lithium layers. However, stable reversible lithium extraction is restricted to 50% - 60% extraction. Nevertheless, this amount gave a reasonable cell capacity at a voltage versus a Lithium anode of about 4 V.

At that time, all we had was a cathode material. The British battery makers were not interested ; they could not imagine beginning with a discharged cathode. A Japanese worker at Sony had been quietly investigating a special waste carbon as an anode host for the insertion of lithium in order to circumvent the safety problem of the battery, and he recognized immediately that my cathode was what was needed to make a high-energy-density rechargeable lithium battery. The Sony Corporation was looking for such a battery to enable marketing of the cellular telephone and the laptop computer. They have done an excellent job of commanding the market. It is my understanding that at the present time approximately 20% of the cobalt production in the world is used in these batteries. Already expensive, the price of cobalt threatens to go even higher. Therefore there continues to be a strong incentive to find less expensive alternatives.

With the publication of our results, Michael Thackeray was sent from South Africa to work with me. When he arrived, he said that he wanted to find a cheaper cathode and that he was inserting lithium into magnetite, Fe3O4. I was surprised because spinels were considered to be gem-like materials having little solubility of interstitial cations. However, I had heard Bruno Scrosati of Rome claim the same thing two weeks earlier, so I told Thackeray to repeat the experiment in my laboratory. This he did, and then I realized that the insertion of lithium was converting the spinel to a rock-salt structure. Both structures have a face-centered-cubic oxide-ion array. In the rock-salt structure, cations occupy all the octahedral sites of this array ; in spinels, only half of the octahedral sites are occupied to form a three-dimensional framework with an interconnected interstitial space of face-shared octahedral and tetrahedral sites. In the LiMO2 oxides, the M atoms occupy alternate (111) planes of octahedral sites. In the spinel, the remaining one cation to four oxide ions are ordered in tetrahedral sites of the interstitial space ; with two Li atoms for four oxygen atoms, the layered LiMO2 phase is more stable. Insertion of lithium into Fe3O4 was leaving the spinel framework intact ; the lithium entered octahedral sites of the interstitial space and pushed the tetrahedral-site iron into octahedral sites in a cascade. When I realized what was happening, I told Thackeray to insert lithium into the spinel Li[Mn2]O4 since I knew that in this spinel only Li+ ions would occupy the interstitial space and the [Mn2]O4 framework, though becoming metastable, would remain intact. This he did, and we found a flat open-circuit voltage versus a Lithium anode of 3 V. Removal of lithium gave 4 V. The possibility of an inexpensive cathode transporting Li+ ions in three dimensions stimulated extensive research on this cathode material even though the Li+ ions do not move as rapidly in this three-dimensional framework as they do in the layered oxides.

Unfortunately the manganese spinels do not retain their capacity on repeated cycling in the 4 V range. In the 3 V range, the flat open-circuit voltage reflects a two-phase range ; as the Mn(III) concentration increases with lithium insertion, a cooperative Jahn-Teller deformation from cubic to tetragonal symmetry occurs, and the deformation on repeated cycling tends to crack larger particles so as to cause capacity fade in the 3 V range as well. Recently, Sun Ho Kang came from South Korea to my laboratory in Texas, and we found that this latter problem can be solved by a simple ball-milling procedure that breaks the particles into many small microdomains. However, it looks like the manganese spinels will be restricted to the 3 V range and will face serious competition from other developments.

In order to increase the free interstitial volume for three-dimensional motion of the Li+ ions, I decided to reinvestigate the NASICON structure, but this time as an insertion electrode rather than as an electrolyte. The hexagonal M2(XO4)3 framework is found with several transition-metal atoms M and polyanions having X = Si, P, S, Mo(VI), or W(VI). For example, hexagonal Fe2(SO4)3 has the structure of the NASICON framework. Although the iron atoms are separated by (SO4)2- polyanions, the electronic transport is better than the Li+-ion transport. I was immediately struck by the observation that in this structure, the Fe(III)/Fe(II) redox couple gives 3.6 V versus lithium whereas the Fe2(MoO4)3 and Fe2(WO4)3 frameworks give 3.0 V. Changing the counter cation in the polyanion shifts the working redox energy just as shifting the Li+ ions from tetrahedral to octahedral sites in the [Mn2]O4 spinel framework changes the energy of the Mn(IV)/Mn(III) couple by 1 eV. Moreover, the more acidic polyanions bring the Fe(III)/Fe(II) redox couple into a useful energy range, thereby making an iron oxide a competitive electrode material. This fact was noted by Shigeto Okada of Nippon Telephone and Telegraph, and he was sent to my laboratory to work on stabilization of the hexagonal form of LixFe2(SO4)3. While he was with me, I asked my post doc, Kirakodu Nanjundaswamy, to investigate electrochemically the relative energies of several transition-metal redox couples in the NASICON structure with (SO4)2- and (PO4)3- polyanions. All the redox energies were found to shift by 0.8 eV on changing from (SO4)2- to (PO4)3-. At that time, my student Akshaya Padhi was looking for a thesis topic, so we decided to broaden the study by investigating lithium insertion into several different framework structures containing polyanions. In the course of that study, we found that all the lithium could be extracted from the olivine LiFePO4 and that it gave a constant open-circuit voltage versus Lithium of 3.4 V over most of the compositional range 0 < x < 1 of Li1-xFePO4 due to a small distortion of the FePO4 framework with x = 1. Professor Michel Armand of the University of Montreal recognized immediately that this material would be an excellent match to the polymer Li+-ion electrolyte that he had developed, so he persuaded the Hydro-Quebec Corp. to license our patent. He and Michel Gauthier of Hydro-Quebec then developed a fabrication procedure for achieving the full capacity on repeated charge-discharge cycles at a practical rate. This electrode material promises to be an inexpensive and environmentally friendly replacement for the present Li1-xCo1-yNiyO2 cathode, but other more competitive materials may yet be developed.

BBV : When did you come up with this new oxide ?

JG : In 1994.

BBV : So it is fairly recent. Were you still in Oxford ?

JG : No, I left Oxford in 1986. At that time, a generous donor had given to the University of Texas $8 M for Chairs in Science and Engineering provided the university could match it. In the end, $32 M was raised for a set of chairs, one of which was offered to me. From the endowment, they pay half my salary with enough left over to pay for a secretary and some expendables. Moreover, I didn't have to retire at 67, so I haven't yet ; I am an old tiger enjoying working here.

BBV :So you have a laboratory facility here ?

JG : Yes, we have managed to build up a nice laboratory in Texas. My battery work has been funded by the Robert A. Welch Foundation of Houston, TX. I am most grateful to that organization. They also supported the student with whom I developed the perovskites as solid oxide-ion electrolytes. Keqin Huang came from China to work with me on a solid oxide fuel cell (SOFC) based on the perovskite electrolyte Sr- and Mg-doped LaGaO3, first discovered by Ishihara of Japan. While still at Lincoln Laboratory, I had worked with a mechanical engineer to propose the SOFC as a bottoming cycle for a power plant ; our analysis was based as yttria-stabilized zirconia (YSZ) as the oxide-ion electrolyte. The DOE has since then provided Westinghouse with massive funding to develop the SOFC. Huang and I systematically developed a package of electrodes, buffer layers, and interconnects for a SOFC based on the gallate electrolyte, which we showed gave a competitive performance to SOFCs based on yttria-stabilized zirconia. Westinghouse has now hired Keqin Huang. It is not clear that the gallate electrolyte will be the winner, but the chemical lessons we learned in the process of building our cell will help in the selection of electrode materials and the use of buffer layers. I believe the SOFC technology, though difficult, will find commercial realization in the relatively near future.

But in 1986, while I was moving to Texas, Bednorz and Müller reported the discovery of high-temperature superconductivity in the copper oxides. This discovery brought me back to my study of the unusual physical properties that are encountered at the crossover form localized to itinerant electronic behavior in transition-metal oxides with perovskite-related structures, a study I had been forced to abandon in the early 1970's. Shortly after my arrival in Texas, a letter arrived from a physics professor at the Jilin University in northern China. He had a student interested in the high-pressure work we had done while I was at Lincoln Laboratory, and he wished to have him come to do a Ph.D. dissertation with me ; the degree was to be granted by the Jilin University. I arranged for the student, Jianshi Zhou, to come to the U. S. as a visiting scientist, and I put him to work on the copper-oxide superconductors. Fortunately for me, he continues at Texas in a most fruitful collaboration. We have used high pressure as a variable that allows not only the preparation of materials not accessible at ambient pressures, but also to monitor the change in electronic properties with increasing interatomic interactions in the region of crossover from localized to itinerant electronic behavior. High-temperature superconductivity in the copper oxides and a colossal magnetoresistance in the manganese oxides are found, for example, in mixed-valent systems at this crossover. I have invoked the Virial Theorem of mechanics to show that we can expect a first-order transition at the crossover with a (M-O) equilibrium bond length that is larger for localized than for itinerant electronic behavior. With this idea, we have demonstrated experimentally that where phase separation would occur at too low a temperature for atomic diffusion, it may be accomplished in perovskite-related structures by cooperative atomic displacements. Where these displacements are ordered and static, they give rise to the stabilization of charge-density/spin-density waves (CDW/SDWs). In a mixed-valent system, the cooperative oxide-ion displacements may remain only short-range ordered, in which case the electrons are strongly coupled to bond-length fluctuations that may either segregate a mobile, hole-rich phase or introduce vibronic particles consisting of hybridized electrons and oxygen vibrational modes. We have published a long review on this subject in volume 98 of Structure and Bonding that I edited. Our emphasis on bond-length fluctuations as the fundamental feature of the high-temperature copper-oxide superconductors has not yet been well-received by the physics community, which has concentrated on the importance of the interatomic spin-spin exchange interactions. Given correlation fluctuations that separate spin-rich and hole-rich regions, the spin-spin interactions clearly play a role, but they are associated with bond-length fluctuations that are a general phenomenon associated with the crossover from localized to itinerant electronic behavior. Unusual physical properties are found wherever the fluctuations are not ordered into a static CDW/SDW or do not give rise to a conventional phase separation as a result of atomic diffusion. However, short-range bond-length fluctuations are not detected directly by conventional diffraction techniques. Professor Takeshi Egami of the University of Pennsylvania has developed pair-distribution-function analysis of pulsed-neutron data that is providing a picture of the structure at time scales less than 10-13 seconds ; the data give direct confirmation of the existence of bond-length fluctuations.

AH : They model it on the computer ?

JG : The data analysis is done with the computer, but the pulsed-neutron data that are analyzed provide a picture of the lattice taken within a time that is short relative to a fluctuation. Egami is a careful experimentalist who was willing to develop a technique that could test our hypothesis directly ; his data are quite convincing, and I am very happy that he has been able to provide details of how these fluctuations order themselves into stripes, a detail that our indirect probes could not provide.

AH : So it's the matching of the neutron data with the simulation of the theory that is convincing because the two of them are similar.

JG : Not quite. There is no theoretical simulation of a model. Rather, there is an analysis of the data that provides a direct picture of the positions of the atoms in a short time interval rather than an average position obtained over a long time period. I believe their data on the copper oxides show that the bond-length fluctuations develop more and more long-range order on cooling to the critical temperature for the onset of superconductivity. I believe they order into a travelling CDW/SDW in which the electronic wavefunctions are hybridized with phonons to become heavy electrons, superconductive pairs condensing from the heavy electrons.

AH : So you don't go to many conferences either ?

JG : I go to a variety of conferences in electrochemistry, ceramics, materials science, solid-state chemistry, and physics. I limit myself to those where I am asked to give an invited or plenary lecture. This usually involves several invited talks a year, at least half of which are in Europe.

BBV : Over your career, you seem to have migrated from one discipline to another, finally coming back to where you started.

JG : I wouldn't say it was from one discipline to another, but from one inquiry to another and back again. But perhaps that's the way research goes, in spirals. I have found myself asking one question of a material at one stage and then returning to it to ask another question at a later stage. For example, when I applied the idea of cooperative orbital ordering to LaMnO3 and La0.5Ca0.5MnO3 to explain not only the structure but more fundamentally the anisotropic magnetic order with the formulation of the rules for the sign of the spin-spin superexchange interactions, Wollan and Koehler had also reported no magnetic order in the perovskite LaNiO3. I realized that the Ni(III) ion must have a low-spin configuration, but the lack of a cooperative orbital ordering as well as of magnetic order remained a mystery as everyone assumed the oxides are ionic compounds. At that time we were interested in how the mismatch of the equilibrium bond lengths of the two cations of a perovskite determined distortions of the structure from cubic symmetry or the stabilization of hexagonal polytypes. I went on to consider how the electronic properties would change as the strength of the interatomic spin-spin interactions increased. The metal-metal interactions across shared octahedral-site faces or edges seemed to be an obvious place to look for this change, and indeed TiO and VO are metallic whereas MnO is an antiferromagnetic insulator in which the Mn-O-Mn spin-spin interactions are stronger than the Mn-Mn interactions. When Morin discovered a semiconductor-metal transition in VO2 that is due to the onset of a CDW, I was prepared to think about it. Below the transition temperature Tt ? 67oC, the octahedral-site V(IV) sharing edges along the c-axis pair by forming V-V homopolar bonds. I realized that a change in the translational symmetry can transform a partially filled, narrow band of itinerant electrons into electrons of isolated molecular clusters. Professor Peierls had suggested such a possibility as a one-dimensional exercise in a physics textbook that I have not read, so the change from a one-dimensional narrow band to homopolar bonding between pairs of atoms of the chain is now known as a Peierls distortion. I further noted that MoO2, which is isostructural with VO2 at high temperatures, showed a similar Mo-Mo pairing at lower temperatures, but MoO2 remains metallic. The Mo(IV) ion has an additional d electron that occupies an orbital involved in Mo-O-Mo p bonding, so it dawned on me that covalent hybridization of metal-d and oxygen-p electrons could make the metal-oxygen-metal interactions strong enough to delocalize the electrons. This realization solved for me the mystery of LaNiO3. Paul Raccah had just joined my group from France and needed a project. I told him to prepare LaNiO3 ; he should find it is metallic ! Indeed, it is metallic. This was the first demonstration that the metal-oxygen orbital hybridization in an oxide could be strong enough to de-localize a d-electron configuration as a result of 180o M-O-M interactions. It solved the origin of the metallic conductivity of the sodium-tungsten bronzes, which had been puzzling since its discovery in about 1951. It also led me to map out where the electrons are localized and where they are itinerant in the single-valent oxides with perovskite structure as well as in oxides where metal-metal interactions de-localize the d electrons. At that time, I was unable to prepare the perovskite family LnNiO3, where Ln is a rare-earth atom, as these syntheses require a high oxygen pressure. Later, in Texas, J.-S. Zhou and I were able to show that LaNiO3 contains strong-correlation fluctuations within the band of itinerant electrons. As the size of the Ln3+ ion decreases, narrowing the s* band even further, these strong-correlation fluctuations order into a CDW/SDW below a transition temperature Tt that increases progressively with decreasing size of the Ln3+ ion. We were also able to show that the strong-correlation fluctuations introduce a progressive increase of a Curie-Weiss component in the paramagnetic susceptibility ; the character of the transition from Pauli to Curie-Weiss paramagnetism in the perovskites was addressed experimentally for the first time.

As another example, I had studied with Don Wickham the magnetism of the rock-salt system Ni1-xLixO, 0 £ x £ 0.5, and observed how the Li+ ions order into alternate (111) octahedral-site planes as x approaches x = 0.5. I was later to go back to this layered structure to demonstrate lithium extraction for the cathode of a lithium-ion battery.

I could cite other examples. Already in my first years at Lincoln Laboratory I understood the need to build bridges between physics, chemistry, and engineering in order to be able to design materials that would perform a desired engineering function as well as to explore the fundamental questions of solid-state science. This interdisciplinarity is the hallmark of materials science.

BBV : Do you think of yourself as a physicist, or a solid-state chemist or...

JG : I am a solid-state scientist.

AH : Don't you identify with any of the established categories ?

JG : Well, I would like the chemists to think I am a chemist, but I'm afraid they think I am a physicist. On the other hand, the physicists think I am a chemist.

BBV : That's like the story about Einstein who is a Jew in Germany, but he was a German in Switzerland.

JG : Well, that's life.

BBV : Yes, it's life. But you have been publishing in several journals.

JG : Yes, of course. I am a Fellow of the American Physical Society, and I publish a great deal in the Physical Review and Physical Review Letters. I also was elected as a Chemist to be a Foreign Associate of L'Institut de l'Academie des Sciences de France as I have published extensively in the Journal of Solid-State Chemistry, in the Journal of Electrochemical Society, and in other chemistry journals. I was elected a Fellow of the National Academy of Engineering because I publish in materials science journals such as the Materials Research Bulletin. Thus I identify with all three established categories and am an Associate Editor of several journals.

BBV : I understand you have strong links with the solid-state chemistry community.

JG : Yes, I do. I believe the solid-state chemistry community has been the most appreciative of my attempts to build a bridge between the chemist and the physicist. I have used the experimental strategies of the chemist to explore problems of interest to the solid-state physicist.

BBV : So finally the physicists are accepting you ?

JG : Yes, but sometimes I think a bit reluctantly by some.

AH : And you also publish in Nature.

JG : Yes, I publish in Nature.

BBV : Have you had any links with the people in Grenoble ?

JG : Yes, but no collaborative links aside from a few with workers using their neutron-diffraction facilities. My ties to Grenoble go back to 1954 when I paid a visit to L. Néel, R. Pauthenet, and E. F. Bertaut long before they built up the great facilities there. In 1954, I was able to take a one month leave of absence in addition to my annual vacation, and my wife and I made a splendid tour of Europe. Since I had been working on spinels, I decided to take a side trip from Switzerland to Grenoble to pay my respects to Louis Néel who received a Nobel Prize for his work on ferrimagnetism in these oxides. I also wished to see Erwin Bertaut who had done much pioneering x-ray diffraction on the spinels, perovskites, and garnets ; Pauthenet made the magnetic measurements. I brought to Bertaut my deduction of cooperative orbital ordering in the manganese and copper spinels, and he was delighted to have an explanation of his observations. From that time I have felt a special friendship for Bertaut and for Pauthenet before his too early death. Louis Néel was kind enough to invite me to give a paper at the next International Conference on Magnetism that was held in Grenoble. When I was in England, I went each Spring to Grenoble to referee applications for neutron-diffraction studies there. I have also been invited for 10-day stints to lecture at the University of Grenoble and at the CNRS Crystallography Laboratory that was founded by Bertaut.

BBV : And what are your relations with Professor Paul Hagenmuller ? He is in exactly the same field as you.

JG : My relations with Paul Hagenmuller also go back a long way. The CNRS decided to diversify from Paris some important scientific centers. Grenoble was the first ; Néel, Bertaut, and Pauthenet built up that facility. In the early 1960s Hagenmuller was chosen to develop a solid-state chemistry group in the University of Bordeaux. Already in the early 1960's, before his building was completed, Hagenmuller came to visit me in Lincoln Laboratory. I strongly advised him to build contacts with the physics community. He has had a little difficulty bringing a physics component into his laboratory, but he did develop techniques for physical measurements and his people have interacted with physicists in Paris and Grenoble. In the late 1960s I was able to accept an invitation from him to spend three months in his laboratory ; it was on that occasion that André Cassalot translated my "Metallic Oxides" into the French book Les oxydes des métaux de transition. I have visited, lectured, and collaborated with his people over the years ; and in 1976, Hagenmuller offered me a post in Bordeaux that I declined in favor of the position at Oxford. I received a Docteur honoris causa from the University of Bordeaux in 1967, and I have served as a CNRS advisor to his laboratory as well as to the Bellevue laboratory of Guillaud in Paris. I have had numerous enjoyable contacts with colleagues in France, including an early invitation from Jacques Friedel to spend a year with him in Paris and acting as examiner for many a Thése d'État at several universities. I have had less interaction with Germany.

AH : Why is that ?

JG : I believe it is just a coincidence. Right after World War II, Germany emphasized the rebuilding of their industrial base. Although there was a strong solid-state chemistry tradition in Germany, the chemists like Rabenau and Hoppe were isolated in different universities and were primarily preparative and structural chemists. The Max Planck Institutes did not establish solid-state centers until relatively recently, and they have been slow to recognize the need for interdisciplinarity. However, I have had a little contact with Arndt Simon and Manuel Cardona of the Max Planck Institute in Stuttgart, but there is relatively little overlap between their work and mine. I served with Manuel Cardona as an advisor to the Spanish CSIRO for several years. I also served as an advisor to the Materials Science Center in the University of Groningen when it was first being established under George Sawatzky on the retirement of Franz Jellinek and Cornelius Haas there. I have been better received in Europe than in the U. S.

BBV : But the solid-state community is small here.

JG : Yes, the solid-state chemistry community is only now becoming prominent in America. When I came to Lincoln Laboratory in 1952, the chemistry departments in this country considered that solid-state chemistry was only an exercise in stamp collecting as the community consisted largely of structural chemists. It was only in a few industrial interdisciplinary laboratories like the Bell Telephone Laboratories and IBM that the solid-state chemists were interacting with engineers and physicists. However, even there they served the physicists and engineers by providing them with single crystals. When I took charge of the small ceramics facility at Lincoln Laboratory, I said to myself that I wanted to make the physicist serve the chemist rather than the other way around, so I said to my people, "We have got to be the dog, not the tail ; we will let the physicists be the tail, not the other way around." I suppose it was that attitude that made Oxford accept me as a chemist.

AH : It seems that you have had quite a lot of contact with the Chinese and Japanese.

JG : I see you have done a lot of homework.

AH : We can see Chinese and Japanese names on your publications in the last five years.

JG : You should also see several Indian names. In my years in Texas I have had post doctoral and doctoral students from China and India as well as visiting scientists from Korea and Japan. I have already told you about J.-S. Zhou and Keqin Huang. My contacts with Japan also go back a long way. My first trip to Japan was in 1961. I had been invited there the year before by Nagamiya, but I could not go then. Junjiro Kanamori was his student, and he went to work with Jacques Friedel when I couldn't get leave to spend a year in Paris. Nagamiya and Kanamori were interested in my rules for the sign of the superexchange interactions and my prediction of cooperative orbital ordering in LaMnO3. There were other Japanese working on ferrites who came to visit me before 1961. One was Shuichi Iida of the University of Tokyo. It was his assistant, Koichi Mizushima, who came to me in Oxford and did the initial experiments on the Li1-xCoO2 and Li1-xNiO2 battery cathodes.

During my visit to Japan in 1961, Pauthenet of Grenoble and I were invited by Eiji Hirahara to lecture in Sendai ; I exchanged Christmas greetings with Hirahara every year until his death and interacted with him on the MnP-MnAs system. On that occasion I was also invited to lecture in Sapporo where I remember the pleasure of eating corn on the cob sold by a street vendor. In 1976, I was invited by H. Watanabe of Sendai to be a three-month visiting scholar of the Japanese Academy of Science, but I was only able to stay one month because I had to take up my new post in Oxford that autumn. I have had quite a few invitations to visit Japan, and I have enjoyed interacting with the scientists there. The Japanese have made a wonderful contribution to my fields of interest, and I have been a member of the Japanese Physical Society since about 1954.

The Japanese were interested in my work on magnetism in the early days and our work overlapped quite a bit. For example, Chikazumi was interested in my analysis of the factors that determine the shape of a B-H hysteresis loop, our discovery of cross-tie domain walls in thin films, and the damping factors that control the speed of domain-wall switching during a magnetization reversal ; he was in the process of writing a magnetism text book. Tom Kaplan, who was working with me in the late 1950's and early 1960's, discovered theoretically the possibility of spiral-spin configurations as a result of competitive exchange interactions ; the same theoretical discovery was made simultaneously in Japan and France, each from an analysis of the magnetic order in a different compound. We had a hard time convincing the theorists that the period of a spiral-spin configuration need not be commensurate with the crystal lattice. Tom Kaplan was interested in calculating the ground-state configuration ; as an experimentalist E. F. Bertaut of Grenoble was interested in deciphering the complex spin configurations revealed by his neutron-diffraction experiments. Both independently came up with the same mathematical formalism. There are moments when the time is ripe for certain ideas to emerge, and people working in different countries come up with similar solutions at the same time. Who gets the credit is important for the individual scientist, but it doesn't really matter for the progress of science.

More recently, the Japanese have been actively studying high-temperature superconductivity in the copper oxides and the colossal magnetoresistance in the manganese oxides. Professor Tokura has a large group growing single crystals, and we have made measurements on a few of his crystals. Mikio Takano, now a professor at the University of Kyoto, collaborated with me on the demonstration of a pressure-induced high-spin to low-spin transition at the Fe(IV) ions of CaFeO3.

AH : So the Japanese with whom you had contact were all in the university world ; it wasn't SONY or another corporation ?

JG : They were, for the most part, all in the university world or a research institute. But of course, SONY commercialized my work on cathodes for a rechargeable lithium-ion battery ; it was the basis of my selection as a Laureate of the 2001 Japan Prize. Because of this work, the Nippon Telephone and Telegraph Company sent Shigeto Okada to me and SONY sent me Yamada for a year.

AH : You allowed them to do that ?

JG : I have always been happy to receive good people who are funded by a home laboratory to which they will return. I don't have many sources of funding. David Nelson at the National Science Foundation has provided support for a post doc and a student and the Robert A. Welch Foundation has provided support for two students. I have had a little miscellaneous money from time to time that has helped me get through some lean times.

BBV : Does it cover equipment as well as students ?

JG : Not permanent equipment, but expendables.

BBV : You said you were interested in developing materials that would perform an engineering function. Do you go after research for industrial development ?

JG : No, I don't do industrial development ; but I do long-range targeted research. For example, when we developed LiFePO4 as a cathode material, we patented it and licensed it to the Hydro-Quebec Corporation. The people in Canada did the industrial development of how to fabricate a commercially viable material. Once I have identified a material that will perform a desired engineering function, I leave it to industry to commercialize it.

BBV : But if you have a problem-solving approach rather than an end-product approach, then the problem that you solve might be used for several end products rather than one. Which approach would you recommend for research productivity ?

JG : Research is productive not only when it produces a commercially viable end product, but also when it increases our understanding. Let me make a distinction between long-term targeted research and fundamental research that uncovers new phenomena or provides the understanding needed to know how to go about designing or searching for a new material for a specific engineering function. Examples of my targeted research efforts are the development of the ferrite memory core, of solid electrolytes, of battery cathodes, of materials for a solid oxide fuel cell, of wavelength-selective films for heating with solar energy, of a sole material for an amplifier tube that emits nearly 100 secondary electrons for every primary electron that strikes it, or our unsuccessful attempt to photo-electrolyze water with sunlight in one step rather than two. Yes, in the process of solving or evaluating these long-range targeted-research problems, we did more than obtain an end product ; we also learned a great deal about materials that not only increased our fundamental understanding, but also was to prove useful for solving another targeted-research problem. For example, our demonstration that a thin buffer layer can be used to prevent a chemical reaction between the electrolyte and the anode of a solid oxide fuel cell immediately suggests fabrication of a bilayer oxygen-permeable membrane for partial oxidation reactions. However, targeted research needs to be driven by a well-defined engineering need and a careful description of the engineering constraints expressed as a material "figure of merit" or some other set of criteria. If the engineer does not have a material in hand that can do his job, he can only turn to long-term targeted research to indicate the feasibility of the problem if not a solution to it. In my view, long-term targeted research is well served when there is a balance of fundamental research that can bring the discoveries needed to resurrect abandoned projects or to inspire new engineering concepts. I try to maintain such a balance in my research group. It would be unfair to ask a student to do a Ph.D. thesis involving an end product that is already under intensive development by industry.

I would also distinguish between the extrinsic and intrinsic properties of materials. For the most part, I have been interested in the intrinsic properties of a material whereas the industrial scientist is often concerned with how to optimize performance by changing its extrinsic properties such as shape, morphology, single-crystal versus polycrystal, or doping level. However, we did stabilize the capacity of the manganese-spinel cathodes by ball milling to create microdomains in our particles. Nevertheless, I am not a typical material scientist concerned with problems of fabrication and manufacture of materials that have already been identified as suitable for a particular end use. That's why I consider myself a solid-state scientist more than a materials scientist.

AH : But isn't the market the ultimate driver ?

JG : Engineering problems are driven by the market. But as a scientist, curiosity is also a driver ; one wants to understand the physical processes that govern the material properties we observe and exploit. Solving a problem in materials engineering may require addressing fundamental scientific questions. These are the problems that I prefer. For example, the market would like an electric car that performs as well as the cars we drive today. An engineering solution would be a direct methanol-air fuel cell. It would make possible an electric car powered by a liquid fuel just as the present-day internal-combustion engine is powered by gasoline. Conversion of the chemical energy in methanol to electric power in an electrochemical cell is a well-defined engineering problem, and the engineering constraints are defined by the performance of today's automobiles. However, to achieve adequate power requires identification of a solid H+-ion electrolyte and probably a better methanol-oxidation catalyst as well. Identification of materials that can perform these functions requires understanding of the processes that govern the phenomena of interest. Until these materials problems are solved, there is no point in proceeding with the engineering.

BBV : It seems to me that when you addressed the problem of an electric car in a 1978 paper, you didn't separate the electrolyte and electrode problems. You appeared to address both problems without separating them.

JG : The electrode and electrolyte problems are clearly separable ; each performs a different function. The anode must be an electronic conductor that catalyzes the oxidation of methanol, CH3OH, to carbon dioxide, CO2, and H+ ions whereas the electrolyte must be an electronic insulator that conducts protons. The cathode must be an electronic conductor that reduces the dioxygen molecule O2 to two oxide ions that combine with the H+ ions coming from the anode on the other side of the electrolyte. Carbon dioxide is the exhaust product at the anode, pure water is the exhaust product at the cathode. The entire package of electrodes and electrolyte must be considered together because the chemical potentials of the electrodes must be matched to the stability window of the electrolyte. With an H+-ion electrolyte, the cathode must be porous to allow escape of the water produced at the electrode-electrolyte interface. In a solid oxide fuel cell, an oxide-ion electrolyte allows use of a mixed oxide-ion/electronic conductor since there is no exhaust product emanating from the cathode/electrolyte interface in this case. Nevertheless, the chemical potentials of the electrodes must still lie within the stability window of the electrolyte.

BBV : Do you think you have contributed more to electrodes or to electrolytes ?

JG : I have contributed to both, but more to electrodes. My contribution to the lithium-ion battery has been the cathode, for example. I have made no contribution to either the liquid or the polymer electrolytes used in these rechargeable batteries. I have pioneered the use of a perovskite for the solid O2—ion electrolyte of a solid oxide fuel cell, but my more fundamental contribution was my early work on metallic perovskites that led the way to the use of these oxides as cathodes of the solid oxide fuel cell ; they include the purely metallic manganese oxides and the mixed oxide-ion/electronic conductors. All of the early fundamental work on metallic perovskites and my later work on perovskite oxide-ion electrolytes have provided a basis for selecting cathode and electrolyte materials, but the perovskite electrolyte faces stiff competition from oxides with the fluorite structure.

BBV : And what is your opinion about a specialized journal for the community of researchers working on solid-state ionics ?

JG : I have not been a strong advocate of specialized journals. On the other hand, solid-state ionics has become an important sub-field of electrochemistry, and I can understand the need for rapid publication of developmental results in a specialized journal. I would expect the more fundamental studies to be published in non-specialized journals. On the other hand, Physical Review and the Journal of the American Chemical Society cover so much territory that there was a need to create a Journal of Solid-state Chemistry. This journal has been quite successful, but I worry a bit that its emphasis may become too much on the preparation of new compounds and their structural characterization as new specialized journals are beginning to pull away papers on targeted research and the physics journals pull away the papers having a strong physics component such as those on high-temperature superconductivity and the colossal magnetoresistance.

When I went to Hawaii to receive the Olin Palladium Medal from The Electrochemical Society, I was struck by the tremendous impact of solid-state ionics on that society and on solid-state chemistry. The fact that people are making a great deal of money with the lithium-ion batteries and that the fuel cells are showing more commercial promise has brought financial support into the field. I expect the LiFePO4 cathode will stimulate the field further. It is cheap and environmentally benign, so it may become competitive in large batteries. I can't claim to have designed it ; but I did have an idea where to go fishing. In any case, the field of solid-state ionics is growing, and journals that cater to the field will undoubtedly prosper.

BBV : One more factual question. You have had a lot of students over the years. Did you teach ? Did you have to teach ? What difficulties did you have with teaching ?

JG : Lincoln Laboratory was a Research & Development facility separate from the MIT campus. During my 24 years there, I had only one Masters and two Ph.D. students and I only gave a short series of lectures, never a formal course.

The system at Oxford is totally different from that of a U. S. university. Students come up to Oxford to read Chemistry with two years of Advanced Level science courses that are equivalent roughly to the first two years in a U. S. college. Chemistry students were selected by each College by the Dons of that College who coached them for three years for a career-making final examination. The Inorganic Chemistry Laboratory provided a mandatory Practical Course and a series of 8-lecture courses that were optional, but generally provided material essential for the big final examination. I gave lectures on solid-state topics that were not necessarily covered in their finals, so the half-life of the attendance in my classes tended to be fairly short. After the final, the students did a fourth year of research for their undergraduate degree. My principal contribution to undergraduate teaching was probably the supervision I gave to those who chose to do this research year with me.

At Texas I am required to teach two graduate courses a year. I have also taught undergraduate courses in Mechanical Engineering and Electrical Engineering. I prefer teaching the graduate courses. Of course, my hope is that considerable learning occurs in the course of completing a Ph.D. with me. Those who have absorbed the most are a few excellent students and the better post docs.

AH : I would like to run with the instrument ball for a bit. How do you see the development of instrumentation having an impact on your work ?

JG : That 's a big question.

AH : Maybe you could start by saying what was available in 1951 when you started.

JG : Let me restrict myself to the field of transition-metal oxides. In 1951, ceramic materials were made mostly with high-temperature powder-metallurgy techniques or hydrothermal synthesis. The use of organometallic precursors to lower firing temperatures was a novel idea. Physicists wanted single crystals. The growth of single-crystal magnetite was a major undertaking and achievement. Zone refining of germanium to achieve single crystals of high purity was being developed ; oxide crystals were grown primarily by the Czochralski technique of pulling a seed crystal from the melt. Crystal growth from a flux was just being developed as an art. Now we have an image furnace with which we are able to grow oxygen-stoichiometric oxide crystals of high purity. In 1951, chemical characterization rarely included the analysis of oxygen stoichiometry ; thermal-analysis instruments were not commercially available, and mass spectrometers were used. High-pressure synthesis was carried out in a few laboratories, but techniques for applying high oxygen pressures were not yet developed. Thin films were prepared by primitive sputtering machines. Since those days, soft chemistry is widely used for synthesis and more complete chemical characterization of ceramic materials has become normative. Films are now deposited by a variety of techniques, many of which were not then available. Laser deposition is an example.

In 1951, the electron microscope did not have the high resolution that is available today. The first direct observation of a dislocation was made at that time. The principal tool for structure determination was X-ray diffraction, but analysis of the data was laborious. The first observation of antiferromagnetic order by neutron diffraction was made at that time. Neutron-diffraction and scattering measurements have now become sophisticated and fundamental tools in solid-state science. The advent of synchrotron radiation and pulsed neutron techniques have enabled direct observation of structure at short time scales, which is opening a whole new field of study.

Various spectroscopies were available in 1951, but photoelectron spectroscopy had not yet been developed and nuclear magnetic resonance was in its infancy. Mössbauer spectroscopy and the laser had not yet been imagined. A principal tool at that time was electron paramagnetic resonance. Impedance spectroscopy for measuring the ionic conductivity of electrolytes was not commercially available.

The superconducting magnet and the SQUID magnetometer did not exist. To obtain a magnetizing field of 50 kOe was a big-science project. The vibrating-sample magnetometer was developed at Lincoln Laboratory by Simon Foner in the late 1950s, and Don Smith of my group developed a vibrating-coil magnetometer that allowed us to do magnetic measurements under high pressure. However, the measurement of physical properties under high pressure is still restricted to a few laboratories.

The development of affordable, powerful computers for data collection and analysis has transformed the accuracy and speed with which measurements can be taken. It has quite revolutionized the experimental laboratory.

AH : So what was the infrastructure of the Lincoln Laboratory, of Oxford, and here in Texas ?

JG : The ceramics laboratory that I inherited at Lincoln Laboratory had high-temperature furnaces, a hand press, a hood, a powder x-ray diffractometer, and chemical benches. We were in the Digital Computer Division ; the Solid-state Division was much better equipped, but our access to their facilities was essentially non-existent as each person in that division had an agenda of their own. However, their mass spectrometer was a service facility to which we had access. We made routine transport measurements on the samples we prepared and characterized structurally. I developed a good working relationship with Jim Kafalas who had developed a high-pressure belt apparatus and was looking for something interesting to do with it. With him, John Longo and I demonstrated the relationship between bond-length mismatch in the perovskites and the hexagonal polytypes. Kafalas also developed high-pressure equipment for magnetic measurements with the vibrating-coil magnetometer. We used pressure to change from one polytype to another and to transform from high-spin to low-spin magnetic configurations. I came to appreciate the pressure variable as an extremely useful research tool. We also acquired sputtering equipment for the preparation of wavelength-selective films and for our MgO-Au composite film. At Lincoln, I relied primarily on developing chemical strategies that could provide important information with the measurement facilities at my disposal. I suppose that is why Oxford considered me as a solid-state chemist.

At Oxford, there was little money for equipment in the Inorganic Chemistry Laboratory. I was not given any significant start-up funding, so I relied on the availability of x-ray diffraction, facilities for chemical analysis, a glass-blowing shop and an electronics shop. I acquired furnaces for my own synthesis needs, the means to make impedance spectroscopy and routine electrochemical measurements as well as the optical equipment needed to study photo-electrolysis. The laboratory also had photoelectron spectroscopy and nuclear magnetic resonance, and I did some collaborations with those working with these instruments. Outdated equipment for electron paramagnetic resonance was put into use in the one systematic catalytic study I made on the phosphopolymolybdates. One group in the laboratory was given a second-hand vibrating-sample magnetometer that proved more frustrating than useful. At Oxford, I concentrated on ionic transport, battery cathodes, and photo-electrolysis ; I did relatively little work on the transition from localized to itinerant electronic behavior except to show that hybridization of the d electrons of a transition-metal atom with 6s2 core electrons of a counter cation could cause a localized electronic configuration to become delocalized.

AH : You just didn't have the infrastructure for magnetic measurements ? You couldn't have gone off and used magnetometers elsewhere in the university ?

JG : I suppose I could have developed a collaboration with someone in the Clarendon, but I was busy with another agenda.

AH : Were you a member of a College ?

JG : Yes, St. Catherine's.

AH : And were you able to build interdisciplinary connections through your college ?

JG : It should have been possible in principle, but it didn't turn out to be practical. When I arrived at the University of Texas at Austin, I was given $300 K as a start-up package and an empty room. Professor Hugo Steinfink had an x-ray diffraction laboratory that he has generously shared. He also had a high-pressure belt apparatus in disrepair that was a copy of the one developed by Kafalas at Lincoln Laboratory. I also had access to electron microscopes. With the help of post docs, I built up first my chemical facilities, including thermal analysis, impedance spectroscopy, a dry box, atomic absorption spectroscopy, an arbin battery tester, and equipment for routine electrochemical measurements. We do our own chemical analysis. We later added a SQUID magnetometer and an infrared image furnace for growing single crystals. J.-S. Zhou has developed measurement of transport and magnetic properties under pressure as well as specific-heat and thermal-conductivity measurements. Keqin Huang also developed apparatus for oxygen-permeation measurements. With our own synthetic facilities, we can develop our experimental strategies without relying on others. If you rely on getting crystals or samples from someone else, they have already done all the routine measurements on it. With only a special measurement technique, you must rely on collaborations. If you want to understand how physical properties vary with changing chemistry, you have to be able to make your own materials. I have always thought that was critical.

BBV : You never rely on others ?

JG : Occasionally we have received crystals that we could not prepare when others wanted us to collaborate by making measurements under pressure ; but for the most part we rely on our own samples designed to carry out a particular experimental strategy. People have also come to me for help in the interpretation of their data.

BBV : When you were at Oxford, did you have contact with other universities in England and Europe ?

JG : Yes. I went to Scotland to examine undergraduates. I also examined D. Phil. and Thèse d'Etat candidates in universities of England and France. I interacted some with Brian Steele of Imperial College, London, and his colleagues ; they were interested in the solid oxide fuel cell. At Cambridge, Sir Nevil Mott was interested in the transition from localized to itinerant electronic behavior, and Greenwood at Leeds was a solid-state chemist who did Mössbauer spectroscopy. At AERE Harwell, I collaborated in a European project with a Danish group on the development of lithium-ion batteries and an unsuccessful attempt to realize a methanol-air fuel cell. In France, the people in Montpellier were interested to interact on the subject of solid proton conductors, and I wrote a long review on iron oxides with Charles Gleitzer of Nancy. Hagenmuller sent me a young man from Bordeaux to work with me for over a year, and Jean Rouxel of Nantes sent me someone for six months. Pepe Fontcuberta came for a summer from Barcelona, and I had some interactions with electrochemists in Madrid. I was also asked to give a series of lectures at different universities in Norway on one occasion and in Germany on another. Emanuel Kaldish of the ETH in Switzerland arranged conferences for young people of the underdeveloped countries in Erice in Sicily, in New Delhi in India, in Cairo and Alexandria in Egypt. I also went to India, a country I have visited several times, as the Raman visiting professor.

BBV : And having this experience in Europe and the United States, do you have any idea why materials science generally never started in Europe as here although they have had a great tradition of solid-state chemistry ?

JG : The brief answer is our mission oriented defense and space efforts. England had a strong tradition in metallurgy and solid-state physics out of which grew a magnificent contribution to physical metallurgy. France and Holland had a strong tradition in magnetism out of which grew, secretly during World War II, the development of the ferrospinels that proved critical not only for the memory of the digital computer, but also for microwave devices. In this country, the development of the transistor was also seminal. Work on the nuclear bomb in Los Alamos and on radar at the Radiation Laboratory of MIT during the 1940s alerted the military people to the power of interdisciplinary research ; faced with the challenges of the Cold War, they encouraged this type of research in places like the Bell Telephone Laboratories, the Lawrence Livermore Laboratories, and the MIT Lincoln Laboratory. The military people also encouraged NSF to establish interdisciplinary materials laboratories in several of our universities. Bell Telephone had a monopoly in the early days, which enabled it to plough back its excess profits into research. In the 1950s and 1960s, the Bell Telephone Laboratories were the dominant player in the development of materials science both because of the changing nature of their business and because of large government contracts to develop military and space hardware. The development of fiber optics is an example of how their mission as a communications company kept them involved with materials problems. With the completion of the SAGE system at Lincoln Laboratory, IBM was chosen to manufacture the digital computers for it. The government allowed IBM to add 10% to the cost for product improvement ; they used these funds to build their Yorktown Heights research facility. Kennedy's decision to send a man to the moon within a decade added another set of materials problems that needed to be solved. Moreover, polymers were proving to be a great commercial success. It was the creation of mission-oriented laboratories and the technologies they spawned that challenged the traditional academic disciplines. Technical knowledge was being created rapidly outside of academia ; the traditional Metallurgy and Electrical Engineering departments were forced to expand their definition so as to include the new technologies and to prepare graduates for careers in these new types of laboratories. France under De Gaulle chose to become independent in military and space hardware, so a strong materials science effort was initiated in France under his leadership.

Also, during and following World War II, companies like DuPont de Nemours and Corning Glass had lively interdisciplinary research groups that produced numerous new products. It is unfortunate that most of these industrial facilities are now starved of corporate funds and must compete for government funding of their long-range targeted research.

The chemistry departments in the U. S. and Great Britain have been slow to build up solid-state chemistry as an interdisciplinary subject ; the inorganic chemistry community has been dominated by organometallic chemistry. The solid-state chemists have been incorporated into the materials science and engineering programs in the U. S. Only now as the engineers look for components at the molecular level are the chemistry departments becoming more involved. France, Holland, and Japan have recognized the importance of solid-state chemistry, but of course their development came only after a period of reconstruction following World War II. Russia has emphasized materials science as it, too, had military and space missions. Germany had a longer period of reconstruction, and their mission-oriented laboratories have all been industrial. The Max Planck Institutes are not mission oriented in the same way as the Department of Defense and Energy in this country, so materials science as we know it here has developed slowly in Germany.

Identity with a clear mission is important not only for the development of materials science, but also for the vitality of an interdisciplinary laboratory. For example, the MIT Lincoln Laboratory was the key player in the development of the digital computer during the 1950s. That success reflected a clear mission. When that mission was completed, the leadership lost its vision for further development of the digital computer, and therefore its most talented experienced staff in this field went elsewhere. By the end of the decade, it was clear that the future of the computer lay in making all the components smaller. Microelectronics was the next logical step. However, the Head of Lincoln Laboratory and the MIT administration did not wish to compete with industry in this next phase, so Ken Olsen took a group of computer engineers from the laboratory and founded the Digital Equipment Corporation. Others were given opportunities for leadership in several corporations. A few months later, a group of engineers who stayed with the laboratory had built a small computer that would be affordable by a single research unit. Wes Clark brought it down to the National Institute of Health where he solved in one afternoon a problem they had been working on for months. It was the first demonstration of the efficacy of a small computer. When he returned triumphant the next day, the Head of Lincoln Laboratory announced, "There will be no wet scientists in this laboratory." Consequently this innovative and motivated group left the laboratory.

On the other hand, there is also a strong cultural component. When I went to England, I found that members of the Inorganic Chemistry Laboratory downgraded targeted research ; "pure" research was only curiosity driven ! Moreover, I was astonished when a leader of a chemical industry told me they were hiring few people with a D. Phil degree because these people were only interested in "pure" research. This dichotomy between curiosity-driven and targeted research in a country where class distinctions are so important has, in my view, been a great impediment to Britain's development of materials science as we know it. In France, on the other hand, the Grandes Ecoles have been developing engineers for leadership posts. A British colleague acting as Director of the Institut Laue Langevin (ILL) laboratory in Grenoble told me that the British equipment salesmen knew everything about sales, but little about the performance of the equipment they were selling whereas the French salesmen were good engineers and could answer the specific questions posed by the experimental customer. France's delay in developing a strong presence in the field of materials science was largely due to the period of recuperation following World War II. Establishing the CNRS laboratories gave science a strong boost. However, the CNRS laboratories, like the Max Planck Institutes in Germany, tend to be built around an individual with a specific technique or area of specialization. They are rarely mission oriented unless they receive supplemental financial support from industry or a mission-oriented government agency. Nevertheless, they do build into the university structure the means to develop interdisciplinarity and thus to bid for targeted-research funds. Without the infrastructure of research scientists and equipment that the CNRS provides, the individual university professor with four or five students is isolated and generally unable to compete with larger groups in targeted research unless it is quite long-range.

BBV : Has it been possible for the European to do away with national identity ?

JG : There are now numerous large-science projects that are European rather than national, and science itself has an international character. However, cultural differences and national identities persist. The ILL in Grenoble, for example, is jointly supported by England, France, and Germany. The Director is rotated every three years between the three countries. Nevertheless, the groups from the different countries each bring a different style, sometimes to the irritation of one another. Also, Brussels funds projects that are required to be multinational. I had one with the French and Danes on batteries and had just negotiated another on fuel cells with the French and Germans when I returned to the U. S. These projects tend to be strategic, long-range, targeted research addressing fundamental materials problems. With the globalization of industry and a NATO alliance, the national barriers to cooperation are breaking down, but a national identity and competition for a market-share will accompany their European identity.

AH : You have just outlined the situation in the U. S., Britain, France, and Germany. Do you have any sense of how Japan fits into this process, or is that asking too much ?

JG : No. Japan has done a remarkable job in the area of materials science. The Japanese have not had a military mission, but they have realized their need to compete for external, high-technology markets. Therefore, they have set up mission-oriented government laboratories in support of their industries. They have also established interdisciplinary laboratories in association with universities ; these undertake the longer-range kinds of research that interests me. The large Tsukaba consortium is an interesting experiment that is well suited to the Japanese style. Japan is a homogenous society with a strong national identity ; its people strive to prove themselves after their defeat in World War II. They have built up an excellent cadre of scientists and engineers that is well supported with a sophisticated infrastructure of equipment ; and they make excellent measurements and theory. In my areas of interest, the Japanese are leading competitors and contributors. I am also happy that there are influential voices in Japan that are aware of our need to find a balance between nature's bounty and its exploitation by man.

AH : Now you are emphasizing the funding for equipment and the design of new instruments. I had the impression when you were talking about your own experience that you were de-emphasizing the role of instrumentation.

JG : I didn't mean to leave that impression. I emphasized the importance of being able to make your own materials if you wish to develop a chemical experimental strategy in materials science. I have used, for the most part, quite standard physical measurements because of the limitations of my own situation. However, where it was possible for me to develop instrumentation, I have supported it. Our most innovative instrumental developments have been in the area of high pressure. With Jim Kafalas, I used high-pressure synthesis of metastable phases and the measurement of magnetic properties under high pressure. Unfortunately my program at Lincoln Laboratory was terminated before I could fully exploit our facility. However, we did enough to attract J.-S. Zhou to Texas, and with him I have used pressure not only for the synthesis of metastable phases, but also as a variable to probe new electronic states in solids and transitions into or out of these states without changing the chemistry. Measurements made at the major national facilities are followed carefully ; they guide our strategies. I have already mentioned a number of these techniques.

AH : Can you point to instrumentation that has actually changed your trajectory, your research strategy, because you can now do things that you couldn't do before ?

JG : My research trajectory has been determined by questions I wanted to answer or by engineering challenges ; but of course the strategies we choose depend not only on our questions, but also on the facilities at our disposal. The advent of neutron diffraction, which allowed precise observation of the positions of lighter atoms such as oxygen as well as of ordered spin configurations, has certainly motivated much of my research even if the predictions made were to be confirmed experimentally by those with access to neutron diffraction. Similarly, the direct observation with high-resolution electron microscopy of extended defects such as shear planes and charge-density waves stimulated my research and clarified my view of solids. Access to high pressures has also allowed me to develop experimental strategies that have proven fruitful in my studies of phase transitions, especially high-spin to low-spin transitions and the crossover from localized to itinerant electronic behavior. I have made occasional use of Mössbauer spectroscopy. The development of the vibrating-sample, the vibrating-coil, and the SQUID magnetometer have played a central role. I should also mention that superconducting magnets have given us access to 50 kOe magnetizing fields that were, in 1951, restricted to a few centers. I have made less use of the laser, but the ability to deposit high quality films has been used from time to time. The ability to grow high-quality oxide single crystals with the IR image furnace has also shaped my strategies. Of course, we should not overlook the influence of computers on the automation of our experiments. The commercial availability of such instruments as Thermal Analysis or the Solartron have also enabled me to move into fields without having to build my own apparatus. Photoelectron spectroscopy is a technique that I have happily used whenever I could get access to it with a collaborative partner. The opportunity to find collaborators can be a great determinant to one's research trajectory.

AH : You have just told us about Japan. Do your Chinese colleagues give you any sense of what is going on in China ? Have you been to China ?

JG : Yes, I had the opportunity to make a fairly extensive visit to China a few years ago, and my colleague J.-S. Zhou keeps contacts there. The first observation is that China is changing rapidly. Under Mao Zedong the lid was on everything. Under Deng, people were allowed to make money, but politics remained tightly controlled. Under the present regime, people are more free to think as well as to make money, and the energies and imagination of the people has been unleashed, but within a nationalistic view and still restricted framework. The people value education. Western high-technology industries have moved their production facilities to China to have access to skilled, cheap labor. As a result, they are transferring manufacturing technical and managerial skills to China. The present government has decided it needs to compete with the world in high technology, so it is in the process of establishing research centers that are well-equipped with the latest tools. They have a big pool of educated talent, and they are beginning to bring back from the West with big salaries those they believe can lead their scientific as well as their technical development. China wishes to emerge as one of the leading countries in the science and technology arena. It is too early to tell how their investment will pay off. For the last 50 years, India has poured a substantial percentage of their gross national product into science and into technical education, but the return to the country has not been commensurate with the investment despite the emergence of excellent Indian scientists, many of whom work in the West. The political culture is extremely important.

AH : Have you seen the laboratories in China ?

JG : I was in China before the decisions were made to put a big investment into instrumentation in science research laboratories. I had no access to their military laboratories ; these were undoubtedly equipped first. At the time of my visit, researchers in the universities were not well equipped. Now the computer network and the cell telephones are as prevalent in the big cities as anywhere in the West.

In the last 30 years there has been a steady increase in the number of Asian students that come to this country for higher education. Many of them stay and make a wonderful contribution to our high-technology corporations and our schools. When I was younger, I was moved to wonder how the U. S. could best help the underdeveloped world to come into the technological age. I thought then we should be helping to set up research laboratories there, which is why I considered going to Iran in 1975. I have now come to realize that providing the opportunity to come to our graduate schools and the transfer of manufacturing facilities to their countries is a much more efficient method of providing help. But the political culture has to be right. It breaks your heart to see the conditions under which so many people struggle for life. Why hasn't Mexico taken off and done something more ? Why does a country like Argentina have 30% unemployment today ? It's sad. It shouldn't be. It shouldn't be like that.

Fin de l'enregistrement.

Pour citer l'entretien :

« Entretien avec John B. Goodenough », par Bernadette Bensaude et Arne Hessenbruch, mai 2001, Sciences : histoire orale, /spip.php ?article28.

Pour citer l'entretien :

« Entretien avec John B. Goodenough », par Bernadette Bensaude-Vincent et Arne Hessenbruch, mai 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article28.

Lieu : University of Texas, Austin (USA).

Support : enregistrement disque.

Transcription : Bernadette Bensaude-Vincent et Arne Hessenbruch.

Édition en ligne : Pierre Teissier

ARMAND Michel B., 2001-09-18

2009-12-24T01:38:28Z

Michel Armand, né en 1946, a été formé à la chimie à l'École Normale Supérieure de Saint-Cloud. Après l'obtention d'une maîtrise en chimie inorganique (matière principale, électrochimie) et un séjour au Département de Science et d'Ingénierie des Matériaux à l'Université de Stanford, il entame une thèse sur les composés d'intercalation pour les batteries à l'état solide au Laboratoire d'Ionique des solides de Grenoble (renommé ensuite Laboratoire d'Ionique et d'Électrochimie du solide, puis rattaché en 1995, avec d'autres laboratoires, au Laboratoire d'Électrochimie et de Physicochimie des Matériaux et des Interfaces (LEPMI). En 1974, Michel Armand rejoint le CNRS où il passera le reste de sa carrière française, avant de devenir, en 1995, professeur de chimie à l'Université de Montréal (Canada). Michel Armand s'attacha à dégager les propriétés électroniques des complexes d'intercalation sels de lithium-polymères. Il a contribué à la mise au point de batteries à base de lithium-polymère pour les véhicules électriques.

Biographie détaillée

MICHEL B. ARMAND (MA) : Just to introduce my career, devoted to solid state chemistry, I would remind you that in France we have a special educational system – with universities on the one hand, and the competitive grandes ecoles on the other. I came from one of these schools, the Ecole normale supérieure de Saint Cloud, where most of the students were meant to go all the way through the system. I chose to go into research. Graduating after 4 years, I applied for a student fellowship to study in the US. When I obtained a Fulbright fellowship, I went to Stanford. My supervisor was Robert Huggins and one of his post-docs was Stan Whittingham. In fact I left before submitting my PhD because I wanted to choose a research topic, namely intercalation compounds and solid-state batteries. My advisor wanted me to work on crystals and bronzes which effectively are very nice-looking but without interest for me. So I returned to France in 1972. I joined the CNRS shortly after, in 1974. The CNRS did not bother me when I did not publish for 5 years and let me supervise students before defending my thesis. I benefitted from great tolerance all through my career. I have far less publications than patents : 80 approximately. I have been on leave from the CNRS for the past 5 years while being associated with the Université de Montréal.

BERNADETTE BENSAUDE-VINCENT (BBV) : How did you get into intercalation chemistry ?

MA : Insertion or intercalation, that was the subject of my thesis. I had envisaged titanium disulfide (TiS2) as a potential candidate for intercalation but it was too expensive, too rare, so I dropped it. My doctoral research mainly consisted in trying several simple molecules as potential electrode materials. Insertion chemistry has been developed in France by Jean Rouxel. He supervised a number of doctoral students who inserted metallic ions into various compounds but he never envisaged the electrochemical applications of this kind of compounds. [En Français :] Il dirigeait un certain nombre de thésards qui rentraient des ions métalliques dans des composés mais il n'avait pas envisagé les applications électrochimiques de ce genre de composés. De même à Nancy, [Albert] Hérold travaillait sur des composés d'insertion dans le graphite mais sans penser aux applications. The first steps into intercalation of graphite were made in Germany in the 1830s by a German chemist. The ionic compounds were discovered by Faraday. He demonstrated that silver sulfide behaves as an ionic conductor. Bronzes with their beautiful rainbow colors were also known in the nineteenth century. Nineteenth-century chemistry was something fabulous. However since organic chemistry captured the attention of most chemists, they did not exploit conductivity. Moreover Dalton had won over Berthollet. They mainly considered stoichiometric compounds, and inorganic non-stoichiometric compounds were ignored. Intercalation compounds prove that Berthollet was right. English chemists name them berthollides. They had only one application in the nineteenth century : it was the famous Nernst's glower. It was a commercial success. Doped "zircone" [zirconium dioxide] is still an interesting material. One more illustration of the well-known law : on commence toujours par tomber sur le bon modèle.

HERVÉ ARRIBART (HA) : How did you begin with polymer electrolytes ?

MA : The best way to use intercalation compounds was to use a soft electrolyte. I mean the electrolytes known at that time like silver compounds and beta-alumina were not suitable because their volume changed and you cannot maintain a good interface. Plastic materials seem more suitable. So it was mainly out of pragmatic motivations that I turned my attention to polymer electrolytes.

HA : At that time intercalation compounds had been studied for about 10 years. Did you participate in this development ?

MA : In the 1970s two schools were concerned with intercalation compounds in France because solid state chemistry was well developed in this country. One was with Professor Hérold in Nancy who studied graphite intercalation compounds. The other was Professor Rouxel's. They worked on TiS2,.... and selenides and all these well-known dichalcogenides...So the chemistry was known. But nobody had thought of using intercalation compounds as electrode materials. In 1970, Stan Whittingham was a post-doc with Bob Huggins at Stanford. He was using bronzes to make measurements of the conductivity of beta-alumina. And they were making good contacts and observing the passage of ions between the two compounds because they were non-stochiometric compounds. But there was no concept of using this compound as a source of ions for storing energy. It emerged in fact in 1972. It was during a NATO conference held at Belgirate in Italy where Brian Steele suggested TiS2, what he called solid-solution electrode and suggested its possible use as an electrode material. At the same time, my own presentation was dealing with graphite intercalation compounds. After that, the field almost exploded. I mean there was an explosion of scientific publications, because first, Stan Whittingham became involved with Exxon in the program for making batteries using TiS2 as an electrode material. Second, the electrochemical community had realized the potential of these compounds. So there was an enormous activity around these compounds which peaked around let's say 1989.

HA : Would you say that the Belgirate conference was the first event ? Who participated ?

MA : You would find the major actors in solid state electrochemistry : Brian Steele, a well-known metallurgist, you had Bob Huggins, Stan Whittingham well-known for the intercalation compounds, Hagenmuller, Jean Rouxel, and the people working on beta-aluminas at that time with Wynn Jones and the people from Ford and from the British programme. The British Railway company was working in this field at that time. So this conference – unfortunately the book is out of print - was the outset of the solid-state chemistry's large role in batteries. Formerly it was known that fuel cells used ceramic compounds but then intercalation compounds would also be used for batteries.

HA : Would you say that solid-state chemistry was a discipline in itself at that time ? And which were the respective roles of American and European scientists ?

BBV : Did you consider yourself as a member of the solid-state chemistry community ?

MA : Yes, I was working in Grenoble, working in a laboratory which specialized in solid-state chemistry, spanning over high-temperature ceramics, beta-aluminas, interfacial phenomena : A quite well-known lababoratory. So I have been, I believe, soaked into this field at an early stage in my career. And also you have to say that there was a definite prominence of France in solid-state chemistry which still lasts although it is not as obvious as it used to be 15 years ago.

HA : This lab that you mentioned, its tradition was also in electrochemistry ?

MA : It was devoted to all aspects of solid-state electrochemistry. It was unique, having a big team of about 40 people solely working on solid state electrochemistry.

BBV : What was the name of the lab ?

MA : At that time it was Laboratoire d'Ionique des Solides. The name was changed when it merged with other laboratories. But at that time it was mainly a solid state laboratory partly working on liquid electrolytes. They were precursors in organic electrolytes. Back to Belgirate : suddenly the people in electrochemistry could benefit from the knowledge on intercalation compounds. I mean the chemistry of intercalation compounds : the crystallography, interpreting structure. This allowed a rapid progress.

HA : Could you say more about the French solid-state chemistry schools ?

MA : In Grenoble there was a tradition of electrochemistry dating back to the nineteenth century. It is an heritage. There is a school of engineering there because there is a need for electrochemists. There was this group which sort of nucleated around Professor Desportes and developed research on high temperature ceramics and spread into all aspects of solid-state conductors, mixed conductors, ionic conductors : oxides, glasses, silver compounds, and so there was a common attitude which was more pragmatic than that of other groups.

HA : What was the status of Solid-State Chemistry in the USA ?

MA : It was mainly pragmatic. It was part of Materials Science departments. There was no per se solid state chemistry groups. When I moved to Stanford, Bob Huggins was in a Materials Science department. There was a strong tradition of solid-state electrochemistry in the USSR. And our lab had strong bonds with laboratories in Moscow working on high-temperature fuel cells and also electrodes for MHD (magneto-hydrodynamics), a possible source for transforming fossil fuels into energy.

HA : Your own background was not in organic chemistry. How did you get this idea of polymer electrolytes ?

MA : Polymer electrolytes emerged from the fact that we needed soft electrolytes for using intercalation compounds. I had no knowledge myself of what a polymer was. I thought that polymers were a perfectly disordered state of matter that they could turn into a glass. On the other hand, the electrochemical community had also missed the fact that soft matter deserved some attention. Solid state electrochemistry was inorganic chemistry. Bridging the gap took at least 5 years.

HA : What was the role of Peter Wright, the British polymerist ?

MA : Oh he deserves credit for having made officially the first polymer electrolyte. He realized that dissolving sodium or lithium salts in poly-ethylene oxide (PEO) which at that time was used as an additive for inks or for enhancing the viscosity of water. He realized that if you make complexes and if you heat this complex it becomes conductive. But what he did not realize, because of the gap between polymer chemistry and electrochemistry, was that such complexes had an enormous potential for making batteries when working in conjunction with intercalation compounds. So when I started myself to consider PEO as a solid electrolyte, while I was in Stanford, I had not heard of Wright's paper. It was natural to think of polymers because the problem was the variation in the volume of the electrolyte. I called a colleague of mine in Grenoble to ask him which macromolecule could be used. He mentioned PEO. I ordered it. I mixed it with lithium bromide, I measured the conductivity. Nothing. I dropped the subject. Later when I read Wright's paper in 1975, I understood that I had lacked intuition. Had I heated above 50°C, I would have observed conductivity. When I saw Peter Wright's paper I thought he had found the compound. Now it has to be generalized. So what was lacking was 1) were these coumponds any real conductors ; 2) could they be made for the metal whose intercalation chemistry was prevalent, i.e. lithium. This was very rapidly approved. There was this presentation in St Andrews and people jumped into the field from both sides : electrochemists started making or buying polymers or and polymer chemists started measuring conductivities.

HA : It seems that understanding the mechanisms of conductivity in polymer proved to be difficult.

MA : Oh yes. The theories were there but there was no common application. The polymerists were well aware that the diffusion or transport of material in an amorphous structure was obeying a special law which was called the free volume law. Polymer chemists knew a theory first proposed in the twenties or the thirties which pointed to a temperature which plays the crucial role from a thermodynamical point of view : the glass transition temperature which determines everything. In solid state electrochemistry, the classical Arrhenius law was obeyed most of the time. In fact if you look after 20 years you realize that the situation is not so simple that in some polymers Arrhenius law was sometines obeyed, and that in very high temperature beta-alumina the free volume is sometimes interfering.

HA : Were there colleagues of yours in Grenoble working on amorphous solids ? Did it help you ?

MA : We had good relationships, scientific discussions about the discrepancies between glasses and polymers. Discrepancies and also frustration because the best conductors not especially for lithium are glasses, compounds which are brittle, hard and in which you imagine that it would be more difficult for ions to crawl than in soft matter like polymers. And to our surprise polymers were very good conductors at 60-80°C, warm, lukewarm temperatures. At room temperature conductivity dropped to almost insulators while glasses remained conductors. This situation has been kept for almost 25 years. Trying to break the tg barrier to avoid having a drop of conductivity barrier when you get close to the glass transition temperature of soft matter of activation energy has been the main challenge of research.

HA : When you started to have contacts with industrial companies did you get into trouble with the CNRS. How did you arrange the contracts ?

MA : As soon as we made the first polymer battery and realized its potential we applied for a patent through the CNRS. We did not realize that the patent filing was delayed a couple of days after the presentation in St Andrews. For us it was not very important because in a naive belief we thought that if you speak publicly you may not have your idea stolen from you. But in fact no, according to the French law, if you disclose your invention it is no longer patentable. In the US you are supposed to be able to disclose your invention and you have ten years to file your patent. You are protected because you are the inventor. But stupidly enough because we did not realize, not knowing the law, the patent was extended one year after its filing date and not the date of the St Andrews presentation. In fact the patent was not cancelled but a number of our claims were withdrawn. Surprisingly, it was possible to keep most of the claims in the European litigation but a re-issue was asked at the patent office in the US. It became a nightmare. I will be very frank and provocative in saying that the US patent office displayed a kind of protectionism : the file was lost two times, the examinor was changed many times. We finally ended up sending a lawyer especially to discuss with the examinor and he said that it was absolutely obvious that the examination should have been made before and so on. Finally the patent was re-issued with one claim just one year before the end of its life. In any case this did not deter Elf Aquitaine to start doing common research on this subject. At this time, oil companies were trying to diversify their activity, -solar energy and so on - trying to have a green image. For a while we worked together and we were joined very rapidly by Morselus Contender which was the electricity utility of Hydro-Quebec which is like PTNE or in the US, Edison or like EDF in France. This company mostly relies on hydro-electric power with a lot of hydro-electric possibilities. The cheapest electricity in the world is in Quebec. And they were interested in my goal, my dream : having an electric car, for pollution reasons.

BBV : Which were the terms of the collaboration between Hydro-Quebec, Elf-Aquitaine and the CNRS ?

MA : This is also a subject of controversy. I will be very frank. The CNRS did something that it would not do anymore because it has learnt the lesson. It gave the property of the patent to Elf-Aquitaine who then sold back 50% of the co-property to Hydro-Quebec. In this sense, I think that whatever the country where I work, the state research bodies – NSF or CNRS or any other agency – should never give up patent property. This was the cause of many troubles because it gave Elf Aquitaine complete power over the future of the project.

BBV : What was the reaction of the CNRS when Elf sold its part of the project ?

MA : CNRS could not object because they had made this mistake of giving the property of patent instead of giving the license. Which should never be the case. The government should always be in a position to make the best use of the research which uses tax money. It should be in control of the output of public research.

BBV : Why did you chose to work in Montreal instead of staying in Grenoble ?

MA : It was supposed to be for one year. And we felt five years ago that we were in the final part of the race. A start-up company was making prototypes. The USABC, United State Advanced Battery Consortium, made the choice to invest heavily in solid state batteries. So I thought that it would be easier to work in Montreal than crossing the Atlantic four times a year.

HA : You mentioned the role of electric vehicle in your research program. How would you characterize the role of state programs ? And the private programs conducted by automobile companies.

MA : In the early eighties there was no serious program in electric cars. There was a small activity. People were interested but they did not believe that the electric vehicle would be emblematic (?) before the mid twenty-first century.

BBV : What was the role of EDF (Electricité de France) ?

MA : They were not interested, in the assumption that nuclear power was so abundant that they would not need it. They did not have the expertise : they needed to work in the field of batteries. They left this role to companies such as CGE (Compagnie Générale d'Electricité). They were certainly interested in batteries for load-leveling but they did not invest into batteries which seemed in any case too far away from applications. The people in charge of developing companies were CGE in France or Duracell in the US or whatever battery companies. People did not realize that the solid-state polymer battery is completely different from conventional batteries in terms of technology : it's more akin to paper mill, or printing technology : we are speaking about thin films, and high speed. Solid state polymer batteries have a high surface, thin film configuration. Inspiration and information came from the paper and the film technologies or printing technology. Batteries and fuel cells are still some of the best for producing electricity locally as a co-generator. Intercalation compounds are used for portable items.

HA : After 30 years what is your feeling about the role of Solid State Ionics ?

MA : Its importance has been reinforced recently by the concern for batteries and fuel cells. Most of the driving forces for Solid State chemistry were in the field of energy, the batteries and the fuel cells.

HA : How do you see the future ?

MA : The future ? We need to use energy more efficiently, to reduce pollution... Definitely the near future will be hybrid cars in which we decrease by a factor 2 or possibly 3 the consumption of the car by coupling a normal internal combustion engine well attuned for working at its maximum efficiency with batteries. The batteries are here to provide power for acceleration and also to absorb power every time you break. That way you make better use of your fossil fuel. This is what Japanese car makers Toyota and Honda are going to commercialize. These companies are losing on these cars but they were overwhelmed by the demand. People creating these hybrid cars are so enthusiastic about the feeling of a soft ride, almost noiseless, and low consumption. Taxi companies in Lausanne are among the first. There is also a niche for truly electric cars. Solid-state batteries are ready. If our information are good, there will be solid-state batteries at the Hydro-Quebec. The company will make them available to be tested by the public at the next electrical vehicle (EV) meeting in Montreal next month. This car can be driven for 200 or 300 km on a single charge which makes it suitable for daily commuters, especially for people with a recharging facility in their garage. These cars are ready and it is just a question of political will. On the other hand, there is definitely some lobbying from oil companies, and car companies are not yet willing to change their habits. They are going to sub-contract the making of electronics for EV, the batteries for the electric motor. So they are going to have a less dominating role in the making of the cars. There is some resistance against such a change. Now that the California law has been passed prescribing 10% of the new vehicles with 0% emission hybrid cars are taken seriously unlike in the eighties. They still have to reach political acceptance.

HA : Beta-aluminas have been considered as model-materials and they prompted industrial developments. Do you consider that there is a future for this material ?

MA : The sodium-sulfur batteries produced by Zebra companies have demonstrated their ability to be used for the EV. It's a question of price. There was also a concern for safety because we are speaking of batteries operating at 300°C but most of these issues have been addressed. The main problem is the cost. It makes sense to work on this Zebra batteries for load-leveling. This battery has an almost endless life. In this case the investment can reach very high levels because there will be a return of investment over 10 to 20 years. So the price is less drastic than for a car whose lifetime is 5 to 7 years depending on the countries. And polymer batteries working between 60 and 80°C are very easy to manage. I believe that 20$ per KW/h for stored energy can be made with a polymer battery because the technology is different from that of conventional batteries. They can be made with a very high volume of production, high speed, high conductivity. The same way paper is not expensive although the machinery used to make paper is extremely expensive. The productivity is enormous. Polymer batteries have the same characteristics.

BBV : The EV is your dream. What attempts did you make to convince and get support from state agencies and car companies ?

MA : There are 3 stages : research, R&D and development. I never had problems at the research level. This was science, we had the CNRS resources. We were lucky in having Hydro-Quebec joining the research team. Michel Gauthier who was the head of the research group in Hydro-Quebec convinced this company to invest heavily in R&D. Several millions of dollars a year for R&D invested in long-term research. By contrast the investment by oil-companies was only superficial. That is why Elf sold the project to a Japanese company who did not contribute to its advance.

Fin de l'enregistrement

Pour citer l'entretien :

« Entretien avec Michel B. Armand », par Bernadette Bensaude Vincent et Hervé Arribart, 18 septembre 2001, Sciences : histoire orale, /spip.php ?article8.

Pour citer l'entretien :

« Entretien avec Michel B. Armand », par Bernadette Bensaude Vincent et Hervé Arribart, 18 septembre 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article8.

Lieu : Paris, France.

Support : enregistrement sur cassette.

Transcription : Bernadette Bensaude-Vincent.

Édition en ligne : Sacha Loeve.

ANDERSEN Jens E.T., 2001-03-06

2009-12-21T23:53:02Z

Jens E. T. Andersen est chercheur au Département de Chimie de la Technical University of Denmark à Lyngby. Dès 1992, il utilise une technique inaugurée par Dieter Kolb et Richard Nichols un an auparavant : le microscope à effet tunnel en milieu liquide, appelé également « STM in situ » ou « microscopie électrochimique à balayage » (SECM pour Scanning ElectroChemical Microscopy). À partir de 1995, Jens E. T. Andersen a étendu la gamme de ses usages du STM in situ de l'électrochimie à la biologie, en imageant des protéines adsorbées sur des surfaces. Il a organisé trois conférences sur la technique du STM in situ en 1994, 1996 et 2000.


Autorisation de diffusion

ARNE HESSENBRUCH (AH) : Could you give us an overview of your academic career ?

JENS E.T. ANDERSEN (JA) : I studied chemistry and physics. I majored in chemistry and got a bachelor's degree in physics at the University of Copenhagen in 1987. I did the Danish equivalent of the PhD for three years in surface science at Preben Juul Møller's laboratory at the University of Copenhagen, doing metal on insulator surfaces. I finished in 1991, after which I got a post-doc at the University of Cambridge, with Dr. Richard Lambert - he is now a professor at the Chemical laboratory. I worked for a year and a half on a catalytic effect denoted as NEMCA, Non-Faradic Electrochemical Modification of Catalytic Activity (figure 1). We wanted to investigate this effect, invented by a Greek scientist in the late 80's, and we wished to check this under UHV conditions. Then I saw this advertisement for a Danish position to implement a technique called in situ STM. Not just STM, but in situ STM, or electrochemical STM. You see in 1990, as far as I recall, or 1991, Prof. Kolb (University of Ulm) and Richard Nichols (University of Liverpool) found that you were able to operate an STM while the atoms were submerged in a conducting liquid, in an electrolyte, like water. This was a sensation. We used LEED (Low Energy Electron Diffraction) imaging to study electronic details of electronic diffraction, but it was very difficult, especially because we needed UHV conditions. It seemed absolutely sensational that one could image something like that under ambient conditions in air in a liquid, just by electrochemical control of the STM tip. That was brilliant, and this really aroused some interest in me. I took this position. I applied with Per Møller at the Institute of manufacturing and engineering here at the Danish Technical University in 1992 to get the job and I was successful. We continued for two years developing the instrument together with DME. So the purpose with this project...

Figure 1. Non-faradic electrochemical modification of catalytic activity (NEMCA) Principle.

AH : So when you started out with surface science, did you know about STM in the late 80s. It was not of very great interest ?

JA : Well it was interesting as such, because we all speculated : is this technique really able to image atoms. What is it that we really see in the images ? Are these blobs really atoms ? But I think in the mid 80's it became evident that you could image a silicon 7x7 reconstruction, and this convinced me that this was some kind of atomic resolution. So it was all a technique that was developing.

AH : So you even knew about the STM in the early 80's. You'd heard about Binnig and Rohrer and you kept an eye on it, but you were not convinced. The blobs had to be...

JA : Had to be something to do with metal conduction bands and the band structure of metals. Semiconductor structures, and maybe more subtle to interpret. But with the silicon 7 x 7 reconstruction it seemed sort of convincing.

AH : And was this common in surface science, or maybe even in chemistry ?

JA : I think it's more or less a part of the education that you keep an eye on some of the new techniques. You see, the question always arises : what is an atom in reality ? At that time Transmission Electron Microscopy was the prominent technique of atomic studies. But it has become less prominent in the light of STM, because the latter is fairly easy to use and also less expensive. But then again one asks, is it really atoms ? At that time lots of people were speculating and still there is not a convincing theory describing all the details of the tunneling experiments.

AH : I presume that by the time Binnig and Rohrer had gotten the Nobel prize in 1986, then there was no doubt that these blobs were atomic resolution. Everyone agreed about this. But there was still not commercial STM's on the market, you couldn't have used STM's yourself.

JA : I'm not really sure, the Nanoscope, was that in 1980 ?

AH : Late 80's. Digital Instruments was only founded after the Nobel prize.

JA : But when they received the Nobel prize I presume they invented Atomic Force Microscopy in the same year ?

AH : 1986, right. But you would have had to build one yourself, and Joergen Garnaes over there [across the road] in the early 90's he was building his own. And he could only buy one off the shelf in 1992, and there was no longer a point in building one.

JA : In 1991 DME was putting the instrument on the market, but I think Digital Instruments, they were much earlier. I think Besenbacher, who was the Danish pioneer, built his own instruments in the early 80's, mid 80's. He's recognized as a real scientist of developing STM also to convince scientists that this is really a technique of the future. I think he made a really impressive contribution there. So I think he did that in the mid-80's, he must have because I started out doing surface science in 1987, and he was well known in the field at that time. [Actually, Besenbacher, Lægsgaard, and Stensgaard built their first STM in 1987.]

AH : So in your own work in 1987, what tools did you use, what characterizing tools did you use ?

JA : I used the most common tools, low energy electron diffraction and electron spectroscopy, Auger electron spectroscopy, electron deposition for building up atomic layers, and high resolution EELS (Electron Energy Loss Spectroscopy).

AH : The whole palette ?

JA : Not x-rays. X-rays is a common surface technique of elemental analysis, but we analyzed by AES (Auger Electron Spectroscopy). I think I was also one of the only ones in Denmark doing high-resolution ELS and analyzing surface optical phonons on insulators. This is a fairly difficult technique, and Preben Juul Møller, I think, was the only one who had the instrument at the time. And together with 2 Chinese guys we made it work properly. So we got some interesting surface optical phonon studies of metallic insulator surfaces. The interface of insulators and metals.

AH : Would you describe how that works ? The instrument, and what you had to do to get it work.

JA : The difficulty is, that it is a very narrow electron beam of low energy and you have to focus it delicately - it's a very delicate focusing problem. You have to optimize with an electrometer where you measure all the currents at the equipment and then you try to focus into the detector, which is a fairly difficult process, and the manufacturer couldn't really tell you how to do it. Just told us optimize, use optimizing procedures. And we were three people, working on this for three months, and then we made it work by a systematic optimizing approach. You can never do anything by trial and error. Optimizing by statistical methods, experimental planning basically. We used the instrument for a fortnight each, and we did as well as we could, a sort of competitive method of achieving the best signals, and suddenly we got the same signals as the manufacture's best signal. But I think it's quite a struggle, and too much of a struggle in comparison to the information you get out of it. But it was fun trying to make this very delicate instrument working. This is interesting for low energy electron studies, when you can do spectroscopy of something like phonons, that's quite interesting I think. And one of the Chinese guys, Guo Qinlin he's now a professor in China with a group of 30 people, and the other one, Dr. Wu Mingcheng, he went to the States and was employed in Texas A&M, College Station and he is still living there. So he did quite a good job and produced very exciting results, it was really good experimentally, brilliant. But then the technique you can study surface optical phonons, and overtones of these optical phonons, it can give you an idea about the electronic structure of the surface of insulators.

AH : So, is this a common thread for you to use new techniques try to stay abreast in most recent technology and use them to find out about surfaces ?

JA : In the sense that they can give us new information inside of how Nature is working, then it's interesting. Some new techniques emerged, I think, that are not that much of a help to something that we know already. When it's complementary, they can be the sort you need to advance only slightly. Some of the really new exciting technologies can do something that was not possible before, such as the in situ STM, where you can study atoms in an electrolyte medium.

AH : And you started using the in situ STM when you got here in 1994 ?

JA : 1992.

AH : But you had an interlude in Cambridge, and you didn't work on the STM in Cambridge. What tools did you use then ?

JA : Mainly mass spectrometry and Auger. I think we may have used electron energy loss spectrometry. Oh yes, we also used thermal desorption spectrometry together with the mass spectrometer to study molecules desorbing off a surface. This was quite an interesting project and we had a close collaboration with the Greek group who invented this technique.

AH : In Athens ?

JA : It may have been the University of Athens. Constantinos Vayenas was the head of the group. And Ioannis Yentakakis was our collaborator at the time. He went to Cambridge and we started this phenomenon under UHV conditions. We succeeded and I was happy to see what was going on, and we went as far as we could interpreting their method. They have brilliant articles in many famous journals where they show how this effect was working. When we got it running under UHV conditions it was not a significant effect, we could not be convinced that this was as brilliant, as they told us it should have been. To this day, a lot of work is going on to study what exactly this NEMCA effect is. So we didn't really finish the project completely because I left for another position, but I got enough information as to decide not to build a career on it. It was something really exciting, a new science and a new idea, a new and novel effect you can study in detail and resolve all the chemical mechanisms. But I think it was fairly simple. It was an increase in oxygen production by the material that was used for the electrochemistry - it was sort of solid state electrochemistry. And a zirconium dioxide ionic conductor where you can pass oxygen ions through a material by electrochemical potential differences. You can also desorb oxygen off the surface, and of course if you got an oxygen consuming process at the surface you will consume the oxygen produced by the material. And in my mind it was all coming from the material, but my colleagues were not quite convinced, so we disagreed a little.

AH : So you agreed to disagree in the end.

JA : Yes.

AH : How did you get to work in Cambridge in this period ?

JA : Well I had been working with Dr. Preben Juul Møller at University of Copenhagen in surface science and it was sort of a natural continuation of the career. You have to apply for vacant positions abroad, and I was maybe overdoing it a little applying for a position at Cambridge. Richard Lambert knew Preben Juul Møller very well. He was familiar with his work on insulators. So I had been working on insulators and metallic surfaces contacts for 3 years and I knew what it was about. And I think also very quickly, within half a year, we constructed the necessary UHV improvements to study this NEMCA effect together with Ian Harkness, a scottish PhD student who made a brilliant job of constructing this electrochemical cell for UHV conditions. It's not trivial to make this sort of system, but we did it within half a year. And then we got a whole year of studying the NEMCA effect which worked quite well. But of course I was extremely surprised and happy that I could get this post-doc position at Cambridge.

AH : The laboratory life at Cambridge is very similar to that of the University of Copenhagen ?

JA : Yes.

AH : Same kinds of equipment same level of funding ?

JA : The funding is better at Cambridge. More students available for the studies, but equipment is similar. The level of science is also basically similar, teaching is probably a little better at Cambridge. I haven't followed the graduate courses, but to my knowledge some of the people there were really brilliant. The young PhD students were really brilliant scientists.

AH : Were you a member of a college ?

JA : No, I was not affiliated through the colleges. I did try to become a member of some of the colleges, but as a post-doc you are not supposed to interfere with college life.

AH : So the people you talked to were people in your field, in your lab.

JA : Yes it was a highly professional and competitive working environment and I think a very good time.

AH : Was it also a lot of fun ?

JA : Well, it was hard work – I am not sure about fun. I had my family with our daughter aged six months. Also my wife was not too happy, it was one of the reasons why we left a little early. We were supposed to stay for 2 years, we left after 1.5 years. My wife also wanted to go back because it was tough when I was working from 9am until late in the evening. She didn't really have anything to do apart from taking care of our daughter. And she has a Masters in music and rhetoric and wanted to use her education. It was a little too boring for her, I think. But for me it was excellent.

AH : And so you went back to the in situ STM ?

JA : Yes, I started with the STM when I arrived back in Denmark. I had never worked with the STM before.

AH : But you had kept an eye on STM all the while.

JA : Oh yes, as a surface scientist you always look out for interesting techniques that are competitive to what you have in your field. And when I saw this atomic resolution in an electrolyte, I couldn't believe it, because you can't imagine the struggles you have to go through to make a metallic surface clean under UHV conditions. And once it's clean you have only approximately half an hour to make all your studies because it adsorbs all the gases even under UHV conditions. Approximately one hour you can keep your surface clean under UHV conditions. By contrast, with the arrival of the STM you suddenly were able to study atoms under brilliant conditions (ambient conditions) with a low cost instrument and you can even deposit atoms electrochemically. You can study the metallic overlayer at atomic resolution while it is being constructed atom by atom. I just couldn't believe my own eyes. My colleagues and the PhD students had a good laugh and they said : “So, you're going into in situ STM submerged surfaces. Well, you will need a diving suit.” I assured them that “No, no, no, it's atomic resolution.” They didn't believe me. We discussed the article and I have to say that even Richard Lambert was really surprised that this was possible.

AH : So you were one of the people that convinced others that this was possible, that this was real.

JA : Well it seemed real. If there is a paper in Physical Review Letters my attitude is always to take it seriously ? And you can study also the references in the particular paper by Richard Nichols. You can see in the references that they had been struggling with various modifications of STM to get this result. So it seemed very convincing to me.

AH : But if someone like Lambert was critical, he must have had a good reason. And you say that...

JA : It's so difficult to get a clean metallic surface and it's so highly reactive towards gases in the background and it will destroy the clean surface in a matter of minutes and then suddenly you can have water on top of the metal adsorbing to the metallic surface and you can still observe your atoms. At first nobody really understood, and they said okay it was an aqueous monolayer or something like that, we observed under liquid conditions. Of course this is not what Nichols told us - It's really metallic atoms deposited electrochemically, you can see atom by atom building up. No doubt !

AH : So Richard Lambert didn't develop a new STM really, he just used it ?

JA : Well he did acquire an STM for UHV studies at a later stage. Maybe he got it while I was there, but he was convinced that this was a technique he also had to consider for catalytic studies.

AH : But he didn't build his own STM. You take an STM off the shelf and use it for new studies.

JA : But it wasn't much off the shelf for UHV conditions. I think there was one Swiss company building UHV equipment for the STM.

AH : So a UHV chamber with an STM inside as a package ?

JA : Yes.

AH : And the job here was advertised for in situ STM you said ?

JA : It was advertised in a Danish union journal. Magisterbladet, I think. Or maybe it was in Ingeniøren.

AH : So the people here, they must have trusted the new technique also.

JA : Well you see, Danish Micro-Engineering produced the instrument already before I arrived. I think they sold 10 or 20 air STM equipments around Europe. So they wished to develop the STM. They considered this to be a minor problem and they employed me to do the job. As a matter of fact, Per Møller who advertised this position wasn't really familiar with science as such, but the purpose of implementing this technique was to use it for bulk electrochemical studies. So he would more easily be able to study corrosion processes under the real conditions in an electrolyte. He also wanted to use the instrument to automate electrochemical deposition. You know, he is an expert in plating. So we would like to optimize plating processes, let's say pulse plating and things like that. We wanted to study such things with the instrument. He also wanted to build small metallic machinery, something like submarines swimming about in your veins, depositing medicals at the right spots.

AH : Nanomachines ?

JA : Nanomachines. Within 10 months we got the desired atomic resolution and we finished development of the instrument. I'm saying we because Carl-Erik Foverskov, an instrument maker at the institute, he made the design for a bi-potentiostat. Actually, I must mention that I visited Richard Nichols. I think that without his help we would have taken much longer.

AH : Where was Richard Nichols ?

JA : Richard Nicols was employed at Schering, in Berlin. Schering is a pharmaceutical company, and they were taken over by a French company, Atotech. He stayed in Berlin for a number of years doing in situ STM. But he helped me out with some of the problems. I visited him in Berlin and he participated in our conferences. He was invited to help us out, and he also delivered some of the gold samples that were necessary to obtain atomic resolution. So he was very helpful. Within 10 months, we improved the DME instrument, got atomic resolution, and it was ready for distribution, ready for sale. They needed maybe six more months before they were ready to sell the instrument.

AH : What was the connection between the Danish Technical University and the DME in your job ? You said there was a DME that started the job how did they influence the DTU ?

JA : The connection was Per Møller, the center leader. He was head of the Center for advanced electroplating at the DTU. In Denmark, such a center must be a collaboration between DTU and a company. I think there must be something like 3 institutions involved. I don't know which was the third, but I think it's Danish Plating Industry, something like that. So it was a joint venture. I think we succeeded. But I remember that Møller wasn't too happy about the outcome, because he wasn't really interested in the scientific achievements. And we even made this instrument work for pulse plating, varying electrochemical potentials up and down very quickly. This influences the instrument, so you lose the imaging, but we could maintain the imaging while doing pulse plating.

AH : What did you do next ?

JA : Then I was employed with Professor Ulstrup, who's a bioinorganics scientist. I never expected to be involved in bio-something. But then suddenly I found myself in the imaging of proteins. I still don't know what a protein is. [Laughter] Today I do know a little about this field. We started a joint venture with Per Møller, and we applied for the [Danish] National Technical Science Foundation and got a three-year project. We were supposed to image proteins, and yet we uncertain about what we saw in the STM images (figure 2). But we knew some other group in Europe was grappling with proteins because if you can image proteins, you can image the molecule of life. That's really a big thing. It took quite a while but we succeeded.

Figure 2. In situ STM image of azurin adsorbed on gold(111).

From Esben P. Friis, Jens E. T. Andersen, Yu. I. Kharkats, A. M. Kuznetsov, R. J. Nichols, J.-D. Zhang, and Jens Ulstrup, 1999, « An approach to long-range electron transfer mechanisms in metalloproteins : In situ scanning tunneling microscopy with submolecular resolution », Proceedings of the National Academy of Sciences of the United States of America, vol. 96, n° 4, pp. 1379-1384 (figure 7). Quoting the paper : « individual molecules and a submolecular central feature of brighter contrast are clearly visible ». Copyright © 1999, The National Academy of Sciences.

AH : Which groups ?

JA : Professor Kolb in Ulm. Well, he is working not on proteins as such. Dr. Davis at Oxford and his group. Prof Allen Hill, also Oxford. They are the prime investigators in Europe I think. They have come up with some of the best results, including the imaging of proteins. So we've been working in parallel towards the same goal and we arrived there sort of simultaneously.

AH : And when did you succeed ?

JA : 1996 I think.

AH : Were in touch with Hansma ?

JA : Not as such, but I asked him for some preprints, and he sent me some piles of preprints and said "I'm happy you're working in this important field." He encouraged us very much and we invited him to our conference last year in 2000, but he was not able to attend. But he's done very good work and I think encouraged us to continue what we were doing.

AH : So these workshops. How did they start. Who took the initiative ?

JA : That's professor Ulstrup. 100%. He took all the initiative. When he saw this instrument and that we were able to image proteins he became very excited because he's a theoretician doing electrochemistry on metalloproteins. He has developed protein electrochemistry together with Allen Hill but from a more theoretical point of view. And then he's got me and the group to do the experiments. This way he could develop his theory. He took the initiative and then we've got lists of Danish companies and foundations who supported the first workshop. It's no problem to obtain funding for this purpose, I think. We even got funding from the Danish National Research Foundation. You know the Carlsberg Foundation in Copenhagen, they've got a house of science, the Royal Danish Academy of Science and Letters. And they supported us so we could use the premises of their Foundation. There was I think 60 people attending the workshop, in 1994.

AH : Was it a conference on STM in general ?

JA : No it was on in situ STM, electrochemical STM, also called scanning electrochemical microscopy. Allen Bard at the University of Texas, Austin, invented a similar method, and he denoted it as SECM - scanning electrochemical microscopy. So there are various denotations of this technique. We say in situ because we image while it's occuring.

AH : What sort of people came in 1994 ? What fields did they come from ?

JA : Well we invited people to display their results in STM in general and we did get some contributions that were not really in situ. It's definitely not under water, it is not in an electrolyte. We accepted more or less a wide range of contributions because there were overlaps also with in situ in many fields : solid state depositions by vacuum evaporation can also be considered as in situ, and can be made as comparison to some of our in situ experiments. But the purpose was to promote in situ STM. We still believe that in situ STM is superior to regular STM. The availability, information, methods, and scientific results you can obtain are more varied, there are many things you can do. So we would like to promote this technique and of course you can also image proteins in air, but we would like to image molecules in their own environment, which is electrolyte environments. And I've also considered to image viruses and things like that. At the present stage we have imaged proteins satisfactorily, and we have been promoting in situ STM also in the year 2000 to make people understand that this is really something worthwhile.

AH : Have you had a conference every year since 1994 ?

JA : No, only in 1994, 1996, and 2000.

AH : Were the people who came in 1996 all in situ STM people ?

JA : Almost yes.

JA : It was absolutely the most important groups in Europe represented at this congress and some invited speakers from the States also present. I think there were a couple of students from Japan, but no speakers from there.

AH : How many people came in '96 ?

JA : There was around 60 people – same as in 1994.

AH : And in 2000 ?

JA : The same

AH : Any change in composition of attendees in 2000 ?

JA : No, the same groups were represented. The focus was more bio-oriented in 2000 because now the issue was protein superstructures. Bio-inorganic imaging, that was the purpose, so there were some new groups.

AH : Is that because you are now more involved in the bio-side, or because the field in general has moved towards bio.

JA : I don't think the field in general has moved towards bio. The prime investigations are still made in superstructures and under-potential deposition, which is mono-layer studies, because in situ STM is the only technique where you can obtain atomic resolution. Subatomic resolution can be obtained even with other techniques than in situ STM. Some groups may consider imaging of proteins as subatomic. It's not really atomic resolution. Superatomic I'd say, not really at a higher resolution but at a lower resolution than atomic resolution. And they don't consider this very interesting because you get some difficulties in STM theory : how does it work when you see a protein ? People are a little anxious that they may be studying artifacts rather than real molecules.

AH : Yes of course.

JA : There are a number of artifacts in STM, it's known for artifacts.

AH : Can we back up a little ? I have difficulties imagining just how you would scan something like a protein where you don't have a surface, right ? You have something more unwieldy - how does it work ?

JA : It's a little surprising when you try to study large features with STM because the tunneling distance is some 10 Ångstroms, and a protein is at least 40 Ångstroms in diameter. Obviously, the tunneling current itself ought to deform the protein completely. And something like the deformation of a protein is observed : it's flattened considerably. The measured thickness of a protein is approximately 20 Ångstroms so it's probably flattened while in scanning. But it needs to be immobilized at a surface, otherwise you cannot get the image.

AH : How do you do that ?

JA : We choose specific enzymes and proteins where you have a sulfide bridge to a gold surface. If you react sulfides or thiols with gold you form a covalent bond that is relatively strong. Sulfides react readily with gold surfaces, and our problem in the first instance was to show that we were able to image proteins that were immobilized properly and the question was : Is one sulfide bridge from the protein to the gold surface sufficient linkage for imaging ? And it turned out it was adequate. There was just one molecular bond to the gold surface from the protein, through this sulfide bridge.

AH : Thank you !

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« Entretien avec Jens E.T. Andersen », par Arne Hessenbruch, 6 mars 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article4.

Lieu : Danish Technical University, Lyngby, Danemark.

Support : enregistrement cassette.

Transcription : Arne Hessenbruch.

Édition en ligne : Sacha Loeve