Sciences : histoire orale

WUENSCH Bernhardt, 2001-01-09

Sophie Jourdin — 2011-11-18T12:26:13Z

Bernhardt Wuensch is Professor of Ceramics with the Department of Materials Science and Engineering at the Massachusetts Institute of Technology. He received his Bachelor and Masters degrees in MIT's Physics Department, and his PhD in Crystallography. He has been at MIT since his undergraduate days with a short interlude at the University of Bern, Switzerland.

Professor Wuensch has given us an interview full of interesting observations both on the history of Materials Science and Engineering and on the history of MIT.

BERNHARDT WUENSCH (BW) : Materials have been around for a long, long time. Glass making was already a flourishing industry in Egypt in 5,000 BC. Pottery is usually one of the landmarks in the evolution of civilization. In fact we are used to designating the level of a particular culture by the materials they used. Neolithic, bronze age, iron age, and this will probably be known as the silicon age. It is a witty observation I can lay no claim to, but it is valid. But the difference between what we know as materials science and engineering today is that these older crafts, and such they were, were strictly empiricist. They did not understand what was happening. To use ceramics, my field, as an example : the word ceramics is derived from the Greek keramos, which means burnt stuff. You take a plastic blob of clay and throw it in a fire ; and suddenly it becomes hard, maintains its shape and becomes impervious to water. Exactly what goes on in that process, called sintering, was not unravelled until the mid-1950s. All sorts of complicated physical and chemical changes take place. The clay minerals that make up most clays, predominantly kaolinite and montmorillonite, are hydrous silicates. The water of crystallization goes off, organic material that is invariably present in clay gets burnt off and then little bridges begin to form between the crystallites. These grow and coarsen, and gradually, rather than having a few grains that are tenuously stuck together, you have grains that are bonded with big vacancies in between the grains. And then the grains grow and the boundaries between them grow and some of these voids become enclosed in the solid. It is a tremendously complicated process driven by diffusion and vaporization processes that we now understand. But the early refractories industries, the clay industries, were based purely on empiricism. And when a particular mine closed down and the supply of kaolin dried up, the processing industry had to start all over again, and work out new procedures from scratch.

In the area of materials, and I would now include metals, ceramics, polymers, and more recently electronic materials, not just semiconductors but also magnetic and optical materials, the four main classes of materials, underwent a transformation from empiricism to something founded on a firm basic understanding. When these materials made the transition from a low-cost, high-volume, primarily structural material (steel in the case of metals ; basic structural ceramics, sewer pipes ; bath room fixtures, dishware and so on in the case of ceramics) to something that was very high-tech, a case where the development of a particular device was limited by the materials available, and improving them required knowing precisely what went on. And what justified this effort was that this was a transition to a very high-technology, high value added application. So, in the case of metals one went from steel girders as metals of construction to high-temperature alloys that went into jet engines and things of that sort. And to achieve those properties and to push those limits required a fundamental understanding of what was going on. In the case of ceramics that transition came perhaps 10 or 15 years later. And some of the driving forces for that transition...

ARNE HESSENBRUCH (AH) : Which decades are you referring to ?

BW : For metals the 1940s and 1950s, for ceramics the 1950s and 1960s. The real breakthroughs there were first driven by magnetic oxides in the very late ‘40s early ‘50s. That began with the radar developed during the war effort. One had to use materials that were magnetic but also electrically insulating because the high-frequency electromagnetic radiation employed would induce currents in an electrically-conducting material causing detrimental heating.

Another application of magnetic oxides was the random-access computer memory, developed here at MIT by Jay Forrester. The material employed is typically a ferrite, and these are double oxides of a general composition, AB2O4, where one of the ions or perhaps even both is a transition metal ion carrying a permanent magnetic moment. Typical compositions today might have five or six different cation components in them – some to control the conductivity, some to create a direction of easy magnetization, some to impede grain growth as the materials is sintered (because you would like small crystallites to prevent the material from splitting up into magnetically twinned domains). And these materials are engineered on a solid understanding of the physics and chemistry of the materials involved.

The other great impetus came with the advent of the space program, and in particular the development of materials for rocket nozzles and for reentry vehicles. I was in graduate school in those days, the early 1960s, and worked summers at a company involved in the nosecone project for the Apollo program. The initial approach to the problem, to get rid of all the heat caused by the vehicle entering and reentering the atmosphere, was to make it out of a gigantic casting of copper – copper being a good thermal conductor and the heat would thus be conducted away into other regions. But that was not terribly efficient : these things were huge, 10 feet in diameter : gleaming and shining, marvellous pieces of technology and materials processing and development. The next stage, largely developed by the company that I spent the summers with, a collaboration that lasted for 15 years, used ceramic materials because they have much higher melting points. 2500-3000 degrees centigrade is not uncommon for simple ceramic materials such as aluminum oxide and magnesium oxide. Simple low-cost materials, but very refractory, very high melting points. But they have one liability and that is that they are very brittle. So the technique that was worked out by the Space Systems Division of AVCO Corporation, in Wilmington, Mass., was again to make a massive ceramic forging of something like magnesium or aluminum oxide, and then avoided the brittle problem by using a refractory metal such as molybdenum or tungsten, formed in the shape of a honey comb – that would provide the strength and resistance to fracture. So this was a composite material. And then, as goes on in many industries, the final and ultimate solution was to make it out of plastic !

Figure 1. Hans Bethe.

This was a theory that was in part developed by one of the great figures in physics : Hans Bethe at Cornell University, who worked as a consultant at AVCO. He developed the theory of ablation. One can, for example, take an ice cube and direct a blow torch on it, and even though ice melts at 0 degrees Celsius, the ice cube will sit there coexisting peacefully, well not peacefully, but coexisting with the blow torch flame, because the flame melts the ice and distils it off as steam and that soaks up the energy. The ice behind that rapidly changing interface survives the nearby high temperature. Well, the notion with the plastic heat shield was exactly the same. The plastic would char, ignite, and burn away, but what was underneath that decomposing layer was at a low temperature and the vehicle and the astronaut inside were protected. So that was an evolution of use of different materials as the understanding of the properties evolved.

To recap : in the early days of the field we saw this transition from an empirically based technology, variable and not controllable, to an era when the fundamental physical properties were understood on the basis of rational chemistry and physics and applied sometimes in extremely complicated contexts – to a case where one could design and improve materials and push limits. At that time, the field was aligned very much along specific classes of materials. There was a metals industry, there was a Journal of Metals, there was an American Society for Metals. There were industries : US Steel and so on. They were based on metals, and even particular sorts of metals. The same was true of ceramics. There were very large refractory companies that made abrasives and grinding wheels. Norton in Worcester, Massachusetts, was one example. Their whole product line was crystalline ceramics. Corning Glass, as the name indicates, was working with amorphous oxides.

There was, and still is, an American Ceramic Society, a Journal of the American Ceramics Society, departments of ceramics or ceramics engineering. And so there was a complete system of education, professional identity, industries, and academic enterprises that were centered upon one particular class of materials.

It happened a little bit later with polymers. The polymer program here at MIT sprung up in very different ways. Curiously, a large part of it was initiated in Mechanical Engineering, simply because the development of the new fibers, nylon and rayon, required a completely different set of machinery to spin and weave these fibers. They had very different physical properties from natural fibers like silk and wool. So again the need for a transition to a new, higher class, engineered sort of material required mechanical engineering – people to learn something more about polymers in order to process them. But again, back in that era, apart from synthetic fibers, when you thought of plastics you thought of some inexpensive kids' toy that would break in 36 hours and you did not really care because it cost next to nothing. Or you thought of polystyrene foam coffee cup, but you did not think of high-technology conductive or optical materials. And that has now become the case.

And then finally with the transistor and electronic devices, one of the great revolutions in our culture. The additional class of materials, silicon, electro-optical materials, came into being.

Finally it dawned upon people that even though these were materials with different properties and problems, having to be processed in different ways, everyone was really doing the same thing. They were looking at the connection between structure on all of its scales, from electronic and atomic arrangements to the arrangements of crystallites in a solid to more massive structures such as iron reinforcements in concrete. Everyone was looking at the connection between structure on all its scales and the way a material behaved. Increasingly, engineers had to learn to use these different classes of materials in concert. My favorite example is an electronic chip. It has a ceramic substrate, usually aluminum oxide, on which electrically active semiconductor elements are deposited and then etched and shaped and changed in composition. You need to have that thing talk with the outside world, so you need metal contacts in order to connect the electronic components to some circuitry. And then to protect this very small-scale structure, you encapsulate the whole works in a polymer. So, for someone to design such devices, he or she had to be familiar with all four major classes of materials, and the interfaces between them and how they behaved. The devices would not be possible without that sort of understanding. Or on the more science-oriented activities : someone who is operating a sophisticated instrument like a Secondary-Ion Mass Spectrometer to measure very shallow composition gradients on the scale of Ångstroms, or someone who is using a sophisticated electron microscope of ultrahigh resolution that allows you to actually see the individual atoms (actually more rigorously : projected columns of atoms in thin film form). They could call themselves a metallurgist, a ceramist, or an electronic materials person, merely depending on what sort of material they put in their instrument. Techniques were the same – sure : the information they were trying to extract and the uses to which it was to be put differed, but still they would all do the same thing independently of the particular class of materials. So that was really the birth of a materials science. It was when this concern with structure and properties began to transcend different classes of materials and the technology required that materials were used in concert. Now there are companies, particular the semiconductor companies that are involved with all these materials, and people have to understand the basic science of the classes of materials and the engineering.

Figure 2. Schéma du tetrahedron

The Merton Flemings tetrahedron of materials science, structure, properties, processing, and performance [cf. figure on the right]. To me processing and performance are pretty synonymous, but this is a very current view nowadays. The older view, and it is one that I still like because of the similarity between properties and performance, is a two-dimensional matrix with the classes of materials as one way of slicing the field and then materials science and engineering as orthogonal cuts to this : the concern with the properties and the processing and performance of materials from all of the four major classes. It is interesting that the older societies, such as the American Society for Metals, which used the acronym ASM, still uses the acronym, but it is now called “ASM International : the Materials Society”. So they have pushed metals alone off at arm's length. They are staying with the times.

AH : What about the demand for interdisciplinarity ? I have heard accounts that materials science as a uniter of all these different strands was primarily a political decision. It is very difficult to unite across departments of a university, and so interdisciplinary laboratories were created from above, in which this interdisciplinary work could take place. In other words, in addition to the development of a logic of the field itself, there may also have been an outside demand pulling the different strands together.

BW : Probably one of the great difficulties in any university setting, particularly a busy one like MIT, is that people are involved in a certain set of problems that they are very knowledgeable in and very excited about, and they can find more than enough for themselves to do. This means that you are perfectly happy working in a particular area and perhaps even achieving prominence in it, but you are really too busy to reach out and think about collaboration. This was particularly true when there were walls between academic disciplines and departments that were far more impenetrable than they are now. There are several observations that might be made. First of all, I think the evolution of materials science and materials engineering as a name in the academic enterprise is something that happened naturally. It was not created by decree. Many of the people who worked in metals had backgrounds in chemistry, and that is also true of many of the people who were transforming ceramics science, developing a ceramics science from empiricism. They primarily had chemistry backgrounds and more rarely a background in physics. But the people doing condensed matter physics were really anxious to be at a frontier and not do practically-oriented engineering investigations. Again the old generalizations don't stand up, but for most people this was the case.

Figure 3. Josiah Willard Gibbs.

Looking at the people who started the ceramics program here, the one I am most familiar with, one of the founders of the Ceramics Society was W. David Kingery whose background was in chemistry. He was a chemistry undergraduate at MIT, and did his doctoral work under the one solitary ceramist in the Department of Metallurgy. Kingery stayed on and became an Assistant Professor. All his friends and colleagues counselled him against it because there would never be more than one ceramist in a department of metallurgy, and he or she had better be interested in the refractories used in steel making. Similarly, a very influential person in the development of the Department of Metallurgy and in Metallurgical Engineering was John Chipman, who was Department Chair for a number of years and the leader of the Department during the critical years of evolution from empiricism. He used thermodynamic understanding, something that had been around for many years, since Willard Gibbs, in order to bring rationality into steel making. That was an enormous contribution to the entire field. Kingery did the same with ceramic materials.

AH : When was this ?

BW : In the case of Kingery this was in the late 1950s, and the developments in steel were about a decade earlier. The Department of Metallurgy gradually became more diverse because the junior people brought in had wider interests than the narrowly metallurgist interest of the people already there. When I entered the Department in 1964, there were two people who had just joined. One was Harry Gatos, one of the founders of the Materials Research Society, one of the first major materials-generic societies. He was brought in from the Lincoln Lab to work on the growth of large single crystals of silicon semiconductor materials which had the purity and the mechanical perfection to have the desired electrical properties. There was a young Assistant Professor whose name was Gus Witt who came to work with an electrochemist. Casting around is probably too strong a term, because he was not looking for something to do. But the person he had come to work with, Phil de Bruyn, had left MIT. He was South African and had a Dutch wife and wanted to return to that cultural setting. So Gus was left without a home. In those days a young faculty member did not usually get a 6 or 7 figure start-up grant of expenses for capital, but rather had to align him- or herself with a senior faculty member who, because of their standing and reputation, were well-endowed with funds. So Gus Witt collaborated with Harry Gatos on the semiconductor program. That was the nucleus of the semiconducting and electronic materials part of the department.

I guess the main point I am trying to make with all these examples is that, at least at MIT, this did not happen artificially by decree. It was a natural evolution. This was not always the case. Once the notion began to grow and to make sense, I think it is fair to say that there were some universities that changed the name of their department to be in keeping with the times. Some universities, for example, had developed strong programs in metallurgy and ceramics, where the two existed side by side in two separate buildings. So this is the first observation : that the evolution in many cases was natural.

AH : And that this was a generational change ?

BW : Partly a generational change, but partly also driven by this transition from empiricism to a rational scientific basis. One of the things that MIT faculty in that period were very, very good at was this process of breathing new rationality and sound scientific fundamentals into many engineering disciplines that were really not far beyond empiricism. The science, chemistry and physics that they introduced were not really terribly sophisticated by today's standards. They had the knack of seeing the opportunity to bring this rationality into a field which otherwise lacked it. I mentioned the materials people, but there were people doing the same thing in other fields, in electrical and mechanical engineering and so on.

AH : And the theoretical tools that they were beginning to share were things like thermodynamics ?

BW : That is right.

AH : Any other theoretical tools that were beginning to be shared in the same period ?

BW : There is another interesting theoretical overlap. I began as a physicist but did my doctoral work in crystallography with one of the world's great figures in that field, Martin Buerger, who was a mineralogist in the Department of Geology, now EAPS (Earth, Atmospheric and Planetary Science) – not earth, fire, and water ! Geologists had a long tradition of descriptive crystallography for minerals found in the field. They too became more analytical. There was a period in the early 1900s when at places like the Geophysical Laboratory under the Carnegie Institution of Washington, worked out phase diagrams for materials that were of geological importance : silicon oxide, aluminum oxide and so on. These were the major rock forming systems but these also turned out to be the materials that ceramists were digging out of the ground. And once you have dug them out and ground them up, they become a ceramic powder. The materials scientists, the ceramists and metallurgists were interested in making things, so they had an eye on kinetics and on how things changed upon application of heat and pressure.

The systems that they worked with were relatively simple, chemically and structurally. The geologists however, were concerned with anything that Mother Nature had provided, so they delved into these enormously complicated silicates and other sorts of minerals, impure, all sorts of solid solution and chemical substitutions, incredibly complex structurally. But it was a static record. It was relatively late that they began to actively investigate phase transformations, something dynamic. The metallurgists and ceramists had been working on solid-state diffusion, oxidation, and corrosion processes for 20-25 years before the geologists became interested in measuring diffusion rates in silicates. They did so in order to understand the transformations that took place in rock implacements, particularly under pressure and hydrothermal conditions. And conversely, the aim was also to interpret the thermal history of the rock with knowledge of the kinetic rates. So there were two complementary views : one of complex materials and a static picture along with the materials science people who were working on similar issues but in a more dynamic sense with simple materials.

AH : It can almost be mapped by today's standard textbook. There will be chapters on the four major classes of materials : metals, ceramics, and so on ; and then there will be chapters on the properties (thermodynamics, electrical, optical, magnetic). And each of these chapters corresponds to the theoretical tools that were beginning to be shared by the communities you mentioned in the 1950s and 1960s. Would that be a reasonable way of describing it ?

BW : Yes. And another chapter that every textbook on condensed matter has to start out with is structure. This is atomic-scale structure in crystals and amorphous materials, but also microstructure : dislocations, imperfections, and vacancies. These control a great many properties to a larger extent even than the intrinsic properties of the material. Also interfaces. Unfortunately if you are writing a comprehensive textbook you cannot spend too much time on this sort of thing. My field of interest and passion – crystallography – is one that is often slighted. I took a lot of ribbing from my colleagues when I joined the Department of Metallurgy : “You are going to have it easy. There are only three kinds of crystal systems : body centered cubic, face centered cubic, and complex !” There was some truth as a basis for that kind of sardonic view. Even today the great majority of materials used in ceramics are cubic. Not all, but the majority are structurally simple.

But then you asked about, since this was becoming valuable in technology, valuable to government enterprises based on those technologies, once the value of this interdisciplinary work was perceived, were there ways to encourage people to work in this interdisciplinary mode ? There were indeed. In the late 1950s, there was an effort to do this that arose in the Department of Defense, from an agency then called DARPA (Defense Advanced Research Projects Agency). This was shortly on the heels of the discovery of the transistor and the great potential for this device in electronics and communication, and therefore in defense. The people in DARPA had the wisdom to realize that, in order to capitalize on the electronic properties of semiconductors, one would have to understand the chemistry of producing these materials and the way of growing single crystals of unprecedented perfection. This brought in the chemists, it brought in the crystal growers and the materials scientists. You also needed to understand the physics of these very complicated electronic structures and the way of controlling them through doping and through creation of proper interfaces. The only way to make any progress on this was to bring together in one place people who were interested primarily in solids but who came to this area bringing the perspective, instrumentation, and the skill and expertise of their particular discipline with a view to collaboration in a very close fashion – that is, not only formulating but also conducting the research. It was probably the late 1950s, before I came on the scene as a faculty member, that DARPA went around to probably a dozen or more research universities – saying : Hey, do we have a deal for you ! We would like to come and make a building for you in which you might care to house the majority of your people working on problems in condensed matter. Initially, the emphasis was on semiconductors, because that was the driving force for this investment. I believe twelve sites or so were selected, perhaps initially ten with two created later. But that was the origin of our Building 13, directly behind the great dome. That building was constructed during the early 1960s and we moved into it in 1965. It housed a great part of the Department of Metallurgy and Materials Science, as the name had evolved by then. Each name change was won at great expense by the Department Chair, since obviously people who had been trained as metallurgists resisted. That united them in a way that nothing else in academia could have done. You can imagine the furor arising from our grand alumni when the word metallurgy disappeared altogether.

In any case, the new Building 13, the Center for Materials Science and Engineering housed, on its 4th and 5th floors, a major portion of the Department of Materials Science and Engineering : the entire ceramics and electronic materials groups, the polymers group (which grew and increasingly took residence on the 5th floor). The electrical engineers, those who were interested in the materials aspects of devices, were on the 3rd floor. On the 2nd floor were the administrative headquarters and the condensed matter physics group. The latter has grown considerably since that time. Parenthetically : this new creation was the second major interdisciplinary laboratory at MIT – the first was an outgrowth of the Radiation Lab that developed radar in the famous wooden Building 20, since deceased, and Building 24. It is now called the Research Laboratory of Electronics. At the end of the war many of those people who had been brought together for purposes of the defense effort dispersed and went back to their home institutions. But some stayed on and that was the birth of the Research Lab for Electronics. This was another benchmark in the evolution of interdisciplinary work. In this case it was primarily Electrical Engineering and attendant design - some materials work. That came into being shortly after the war, early 1950s.

The charter for the Center for Materials Science and Engineering (and the organization had slightly different names at different institutions) was that first you will conduct materials research in a highly interactive and interdisciplinary mode – and faculty from as many as seven different departments at MIT had participated in the programs. These workers were to be grouped together in teams called Areas of Thrust in early semiconductor research, but later broadened considerably. The other thing that was visionary was the realization that in order to conduct first-class research one needed sophisticated, first-class equipment – constantly evolving and growing more sophisticated. This was too expensive to obtain for any single faculty member or small group of faculty. And moreover, for it to be effective and working at capability, it required support staff. So, the second mandate besides creating these funded, collaborative, and interdisciplinary research teams was to establish central research facilities. For a time, the Center had as many as 12 different central facilities. The next thing the sponsors did was to seek to convert young faculty to this interdisciplinary mode of operation. In order to do so they provided seed funding. It was an unabashed attempt to seduce young faculty into these interdisciplinary teams !

AH : Seed funding refers to a couple of years' funding which would then be taken over by the hosting university ?

BW : No. The Center operated under a block-funded federal budget. Seed funding was intended to provide an opportunity for a young faculty member, someone who might otherwise not be attracted to participate in the interdisciplinary teams. To develop this connection they wanted to get to them early and make it worth their while to not identify only with their peers in their own department. The hope was to fold such young faculty into one of the Areas of Thrust. There were also some features of this program that were almost without precedent : a great deal of local autonomy was given to the Director of the Center. The Director decided what problems to address on the basis of the resources unique to the particular host university. Rather than having these Areas of Thrust (generally speaking there were three or four) monitored by some program director in Washington, they were monitored locally. And this Director presumably would be gutsy enough to pare off the team members who were not interacting sufficiently or whose expertise was no longer needed for a new direction to be taken. It was a thoroughly enlightened view that somebody on the scene would be better equipped than someone down in Washington. This is not true, even in individual research grants, today. The NSF gives grants on the basis of promise, and once you have received the grant you can change minor details, but you cannot start off doing ceramics and then suddenly decide to do fruit fly genetics – at least not without major questioning from the NSF division. Other agencies, the Atomic Energy Commission, and then the Department of Energy, wrote not a grant but a contract : and you had to be very specific about your research. You had to prepare a work statement from which you could not depart without permission of the program director.

This made the Materials Research Laboratories very lean and fast on their feet. If something came up, they could change direction instantly. One of the great success stories here was in high critical-temperature oxide superconductors. When Bednorz and Muller made their earth shaking discovery [of superconductivity in ceramic materials], any number of people dropped what they were doing and began bootlegging efforts to identify these phases and understand this peculiar behavior – which is still not well understood. The Director of our Center for Materials Science and Engineering at the time brought together everyone at MIT who was interested in these materials, and obviously that number was rather substantial, and selected individuals to develop an area of thrust. And with one or two months' notice another Area of Thrust was cancelled : one concerned with defects in semiconductors. Now that may seem like a very courageous thing, but in fact many of the people working on these defects were also interested or even more interested in superconducting materials. People were working in everything from growing single crystals of the materials for basic property measurements. People in condensed matter physics ended up using these crystals – some very, very critical measurements in magnetic ordering and magnetic correlation lengths. That was the first clue that something in the magnetic moments of copper ions was critical to this behavior. Other materials scientists were interested in learning how to make polycrystalline specimens, so that the superconducting properties could be used in making better magnets. Since these were not metals, unlike all previous superconductors, it was not at all clear how you would wind them into solenoids to make high-strength magnets. That particular part of the effort at our Center led to the first US patent granted for processing of an oxide superconductor, and in fact it eventually led to a very successful spin-off company.

The only other thing that needs to be said about the program is that it evolved over time. The typical tour of duty of the Director was five years because by that time the necessary decisions had offended enough people for a new Director to be brought in. The change came towards the end of the Eisenhower administration, when Eisenhower coined the famous phrase : the military-industrial complex. There was a growing concern that the military had control of and sponsored much work, such as basic research in the space program, and that this belonged more properly in the civilian sector. So, at that time, the leader of the Senate, Mike Mansfield, tagged onto the Defense Appropriation Bill an amendment named after him, that confined the military to weapons systems and maintenance and support of armed forces. But they should not be in a position of supporting basic science. That is also interesting historically because one of the prime sources of funding for basic research prior to that had been the Office of Naval Research. They supported a lot of very fundamental science that had only indirect long-range connections with naval defense systems. So the amendment brought about momentous changes : the National Science Foundation's budget was beefed up ; it grew exponentially. I think NASA was set up at approximately this time. It absorbed space programs that had been conducted under the auspices of the Air Force and the Army – I think it is fair to say with considerable overlap and duplication. I think that also the Atomic Energy Commission and the Department of Energy came about then too. The military aspects of atomic energy stayed in the hands of the military, but the peaceful uses were spun off to the civilian agency.

What happened to the Materials Research Laboratories ? The NSF was very impressed with the success of this approach. The whole justification of it is that the net effect should be far and away above what could be achieved single investigator grants. And these investigators might or might not collaborate. There was arguable evidence that this was the case. The NSF toured these Materials Research Laboratories and announced that they would take over the sponsorship of the program.

Things stayed in this form until about seven years ago (1994), when there was some concern that, successful as the program was, it appeared to have become an old boys' club, in that there was no sunset clause. True, the programs were reviewed every three years with a major site visit lasting several days ; proposals were critically reviewed by outside referees, as is the case with any research proposal. Nevertheless, there were some materials activities at universities that were better than others, perhaps because of a critical number of faculty involved and also, one might say, because of the quality of these universities. I am aware that this may sound smug and immodest, but the situation was ripe for sour grapes, and there was a lot of grousing. Politically, a lot of states realized that a way to give the state economy a boost was to start up a research university that attracted industries and created jobs leading to tax revenues and so on. So there were sour grapes. And the MRL program had indeed gone on for a long time. It was competing with a similar program that had been created during the Reagan era. This was created as a response to Reagan's address with words to the effect that we needed to get this country going again, to be competitive and to rev up the economy. The NSF went to Reagan with a proposal to create something called Science and Technology Centers. Very similar in concept to the Materials Research Centers, with two exceptions : 1) they had a sunset clause in them (seven years) ; and 2) they were to focus on a specific problem, and could not shift and change, grow and evolve. They had a much greater emphasis on the outreach to technology and to the professional community : newsletters, training courses, bridges to industry to implement the technologies were integral to the Science and Technology Centers. So we had MRLs (successful, but oh, what have you done for us lately), and the S&TCs. And about seven years ago, just after a director of the NSF had resigned and the directorship of the Materials Research program had changed hands, Congress decided that the entire program should be looked at anew. As the result of a study that took place over a very, very short period of time, the system was changed into something called the MRSECs (Materials Research Science and Engineering Centers). I love the name because as an acronym it is gender blind : they can be either Mrs. Ecs or Mr. Secs ! A masterful political ploy. They supplanted both the Materials Research Laboratories and also the Science and Technology Centers. The funding level remained pretty much at a comparable level. Now there is a notion that, for the older programs, the bar should be raised consecutively at the time of renewals and there should be a chance for creation of some new MRSECs. This is taking place : some of the older MRLs have lost their support and new programs have come into existence, as MRSECs.

So much for institutional support ! But that was a conscious effort to advance materials research in general but also to deliberately foster this interdisciplinary, collaborative mode of work on materials.

AH : You have talked about the theoretical developments, from the institutional perspective, and the funding. Is there a story to be told about the history of the instrumentation ?

BW : When one discusses the history of instrumentation one immediately gets very specific. There are tools such as electron optics that have had a wide application from medical science to inorganic materials research : physics, chemistry, and geology and so on. It was a tool with unprecedented resolution. But it gets very specific. It is true of the way I have operated on my own research path. I always kept an ear to the ground to new apparatus that might provide something new in terms of precision, resolution, or more flexibility, or permit doing something that could not previously be done. Often, these new instruments came into being in fields that were distinct from your own area. Apparatus has become increasingly complex, and companies have made new designs and developed them to a high level. The advent of powerful computers have changed research in a major way. The speed and means of collecting data, the way in which it is analysed, the sort of analysis of a problem that can be undertaken have all changed in ways that could not have been anticipated a few years earlier.

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« Entretien avec Bernhardt Wuensch », par Arne Hessenbruch, 9 January 2001 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article133.

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Entretien avec Bernhardt Wuensch, par Arne Hessenbruch, 9 January 2001

Lieu : Dibner Institute, USA

Support : enregistrement non précisé

Transcription : Arne Hessenbruch

Edition en ligne : Sophie Jourdin

WHITESIDES George, 2002-01-28

Sophie Jourdin — 2011-11-10T17:04:18Z

George Whitesides

Mallinckrodt Professor of Chemistry, Harvard University

George Whitesides' group in Harvard's Department of Chemistry and Chemical Biology works on many topics : Biomimetics, Biosurface Chemistry, Complexity / Emergence, Materials Science, MEMS, Microfluidics, Micro- / Nanofabrication, Photonics, Polyvalency, Self-Assembly, Surface Science, and Tools for Biophysics and Biology.

BERNADETTE BENSAUDE-VINCENT (BBV) : Do you see any changes that you would like to mention in your field over the past 20 years.

GEORGE WHITESIDES (GW) : 20 years ago there was not any materials science in my field, which is organic chemistry. People made polymers, but they didn't really think in terms of materials, and all of this stuff of electronics and optics and unusual functions and biocompatibility and things like that were - some of them were not even concepts and some were not considered materials science because nobody thought about materials science. Materials Science in the last 20 years has come from something that was done with airplanes to be a real part of chemistry - that is really interesting I think.

BBV : Have chemists been involved from the very beginning or did they jump on the bandwagon later ?

GW : Well, no, I guess my sense would be that chemists were involved from the very beginning in the sense that they made materials. Because after all most materials in the world are actually made by chemists.

We have metals, but ceramics often come out of chemical backgrounds, and all of polymers come out of chemistry but they were thought of as being fibers or coatings or something else and the idea of thinking about them as materials - it's a re-naming but it was helpful for the field to think about how to organize itself intellectually among other things, and then what was a little bit of a change was that at the beginning the financial support was primarily from the DoD for its own purposes which was primarily metals and ceramics for airplanes and armor and hot-sections in engines and things of this kind. It is recently that this has changed. Chemistry and chemical thinking is an increasingly important part of materials science which means there is now some money which means it is worth the effort for chemists to think about that as a community they might want to be involved in. But chemistry has gone from an area dominated by the notion of making natural products to an area in which probably the two interesting areas are bio - and most people would say this is the biggest deal in chemistry at this point - and materials. Synthesis becomes an accessory technology which enables one to make these materials that you might want for either biological applications or materials applications.

BBV : And what about the electronic applications for chemistry ? Is there any future in that ? You have been working a lot in that.

GW : I think that is going to be one of the big deals in electronics. The argument there is that there is a certain specific way of thinking about electronics which is silicon and semi-conductors and that works fine. But my prediction is that there is going to be a new class of devices that is going to be perhaps slower but much cheaper, so that the ratio of benefit to cost goes up but primarily because the denominator goes down rather than because the numerator goes up. The notion with these and with optical photonics systems and with organic LEDs is low cost, ease of fabrication, the ability to integrate a bunch of different kinds of functions in the same thing whereas if it is all polymers you don't have to worry about compatibility between the 500-degree processing step and an ion-beam step or whatever it might be. That is organic chemistry. There are two components : one is the laser and the second is the coating. Optical recording now dominates a certain segment of that industry and it is entirely because what chemistry has made possible. CDs are the same thing. These are optical CDs but the older CDs were the same thing. I think chemistry has found opportunities in thinking about the collective properties of matter as opposed to thinking of the properties of individual molecules - it is a little bit of a revelation but it opens all kinds of doors.

ARNE HESENBRUCH (AH) : Shall we try to get at the history of the last 20 years ? What in your opinion has been the most important changes in the last 20 years ? You have been in the field for that long.

GW : It is more like 20 years. I really began to think seriously about materials science when I came to Harvard. At MIT I was primarily concerned with inorganic chemistry and catalysis. So I came here and became involved, but what made a big difference from our point of view was the development of self-assembling monolayers. Self-assembling monolayers were particularly interesting - and I think actually very interesting for many chemists because they made the point that you could design molecules and thereby control macroscopic properties. You make a kind of molecule and a drop of water beads on the surface and you make another kind of molecule and a drop of water spreads on the surface. So that idea of being able to engineer macroscopic properties based on molecular-scale synthesis was a pretty interesting idea and fairly new at the time.

AH : When ?

GW : That happened ... the first identification of SAMs per se was early '80s and forget exactly when, whether it was '83 or '84, and then the real understanding that you could put them together was done by Ralph Nuzzo - he did the first identification of these as structurally ordered systems. And then we did a lot of the work that connected them with materials ; we were actually working on it at the same time and we started publishing papers in the period of 88-89. So it's really only been about a decade. Now polymers have been around for a long time and we have been working on polymer surface chemistry in the late '70s. But we didn't really call it materials, we called it polymers and it was very hard to do because you couldn't really get a grip on it. You'd start with a piece of polyethylene and we used to put in chromic acid solution and that burned the surface and introduced a bunch of carboxylic acid groups which we could use for various purposes but it was very hard to characterize these things and the surfaces were pitted as a consequence, so we never really had a good grip on the density of surface functionality, the roughness of the surface or any of those things.

AH : What did you do to characterize ?

GW : We used XPS and we developed a whole series of techniques like contact-angle titration - which is an idiot idea but the notion that you make the drop more and more basic and you see if it spreads more and that tells you if there is an ionizable group. This is the kind of thing a chemist thinks of first but not a materials scientist with a metallurgy background because they don't know that carboxylic acid groups exist. Self-assembled monolayers still are, I think, the best of all the materials systems - and this is almost independent of field : ceramic, metal or anything else. If you want something which you can control in exquisite detail it is this. If you want to understand how you go from atomic and molecular level structure to macroscopic property within the range of things that it can do, nothing beats SAMs.

AH : And you knew this in the early '80s already ?

GW : No, what you knew in the early '80s was that there were ordered structures. Strictly speaking, well before that, the electrochemical guys had known that organic silver compounds adsorbed on metal electrodes. So that was well understood and they'd been used empirically for a bunch of things having to do with adhesion so there was, as in everything in science if you look backwards you find, lots of precursor phenomena. And then Ralph Nuzzo and a guy named Dave O'Lara(?), who were at Bell Labs at that point got involved in this and I think their initial interest (I actually never asked Ralph why he got into but I think it was partially because they needed ways of doing coatings of metals and - anyway they were good spectroscopists - and Ralph looked at these structures and recognized from the infrared spectra that they were highly ordered so that the idea was that it was not just going on the surface as scrambled eggs but that it was crystalline. And then we did physical organic chemistry. We took that platform starting in the early '80s and put functional groups on the terminal positions so that after the thyols formed mono-layers, you just saw a monolayer of the terminal functional group, and the hypothesis was that this would control wetting. And it did. Then the process from there was that in the early '90s we had the idea that one might be able to make patterns with these self-assembled monolayers and we had several approaches to this - the earliest one was actually an experiment I did with my own two hands - which was to take a piece of a gold dish (gold on silicon), put on a hydrophilic thyol so that water spread on it. We took a razor blade and put some scratches on it and redipped it in a hydrophobic thyol, so one ended up with scratches about a 100 microns wide they were hydrophobic in this sea of stuff that was hydrophilic then put drops of water on it and the interesting fact was that the water would not cross the lines. Had the characterization changed by then ? By that point the characterization was in pretty good shape, the combination of reflection infra-red and XPS did a lot of it. I forgot when people first saw STM images but it was ...

AH : The Nobel Prize, DI began selling in 1989.

GW : Right, and they were hard to see at the beginning because they require the tip to be far away, so it was not the first thing that was done, but people began to see crystalline rays (?). We had done a fair amount of work in the mid-80s on transmission electron crystallography. We'd taken awfully thin gold foils and run electron beams through them and seen diffraction from the organic mono-layers I think those were the first real structural indicators other than the infra-red spectras that they were united. So anyway, we started the business of stamping. I think the first paper was 92, 93, something like that. That became the basis for micro-contact printing and then for soft lithography and that brought an entire new community into it who are now on the other side of the electronic guys who are looking for new ways of getting around diffraction limits and looking for a different economics. And it has not yet made an enormous difference in microelectronics although it may well in this next stage of all-organic electronics. But soft lithography was probably the most important thing in moving the micro-fluidics community away from silicon to polymers. Now, in the long run whether the microfluidic systems we use for genomics are based on polystyrene or PDMS or what, remains to be seen - it will be whatever is cheapest. The basic idea that you did not need silicon, and in fact didn't want silicon or glass for microfluidic systems : all you wanted was that it was cheap, transparent, and easy to work with, and that is polymers. And now you put those kinds of things together with the idea of conducting or photoactive polymers and ever-increasing resolution of these printing and stamping techniques and the economics which are just phenomenally better than traditional methods when you don't need the kind of precision that the photolithographic methods bring, and you find all of a sudden that there is a new approach to making micro- and nano-structures. It is an interesting evolution. What about the biological ? Well, the biological has also been a big deal and the issue there is interesting on a couple of levels : one of them is that biology since the 60s, which is when practical sequencing first really started, has been profoundly reductionist. The whole notion is that you get the gene sequence and everything comes from that by some unknown process. That is not true of course. People now understand that it is not clear what one does with the information of the genome : which will be useful, how you combine that with proteomics, which will be useful in cell biology, which will be useful in knock-outs, which will be useful in the ... and so on. These are all interesting questions that we don't know the answers to. Biology is pretty complicated. In developing biology, as in any field, you need new tools. And new tools are microfluidic devices for genomics, new ways of manipulating cells which have to be in fluids.

AH : Could you put some dates on those new tools ?

GW : They were done in silicon in, maybe, the 70s. The guy who did this was named Andreas Manz who is now at Imperial College in London. At that time he was at Sandor ... Ciba-Geigy ... I forget.

AH : Basel, anyway.

GW : He was in Basel - I think he was in Ciba-Geigy. Of course it was an internal project so none of it was published at that point. He had two post-docs, one named Mike Ramsay, the other named Jed Harrison who were both migrant ; Mike to Oak Ridge and Jed to Edmonton, Alberta, where they started to make microfluidic systems. And that is really where microfluidics started. Other people, Roger Howe, did have an important contribution. In fact, Andreas made some of his first systems out of PDMS - unpublished stuff - he recognized the virtues of this nice elastomeric polymer even back then. But he couldn't publish it and I think the company wasn't very interested, so it sort of languished for a period of time and then this genomics came along and there was this need to find better ways to crank out data large quantities of data. Then there was a real need for microfluidic systems that were parallel with which you could generate lots of information. That was an enthusiasm that began to build in the 80s, late 80s, and people had been making devices using silicon microfab technology and it was clear it was just too cumbersome - it took too long ; they didn't have any control over the surfaces and then we among others made the point that if you use self-assembled monolayers you could get exquisite control over the interface between the materials world and the biological world. We have done a lot of this in collaboration with a guy named Don Ingber here at the medical school. This is in the late 80s, actually the most interesting part of this began came fairly rapidly after we began contact printing or that is when you saw some really neat things. So this was, I would say, 1994 or 1993, I forget when the research was done, but in that period of time. So that was one theme in this : that you could make the inorganic materials of gold films, or whatever they were supporting, you could make them compatible with biology using self-assembled mono-layers. But at the same time other people had begun to tinker with different ways of making micro-fluidic systems. I don't know that I can say what all the threads were, but certainly one of the threads was a discovery that we made that instead of using photolithography and clean rooms and all the rest of that you could do the design, print them out on a printer at scales that were perfectly useful for this kind of work and then you could design quite sophisticated systems. Other people were designing quite sophisticated systems at the same time using conventional lithographic methods. We made a point that you could do it very easily using these soft lithographic methods and that provided quite a stimulus, not to the generation of the final systems necessarily, but to the process of invention because lots of people used those rapid prototypic methods for trying new kinds of devices. This has also been an area where the industrial groups, particularly start-ups, have had a very big influence on things. Probably the first company that was a serious effort in this was Caliper. Caliper was a Larry Box(?) special and it's doing okay as a company. It is focused now on micro-fluidic systems for high-throughput screening for the pharmaceutical industry - it was one of the first to do that. There was a fellow named Lee Hood(?) who was named Hunkerpillar(?) - I think a bioengineer - developed a series of devices for sequencing of DNA and proteins which were commercialized by a company called Applied Biosystems which was one of the early darlings of the biotechnology industry, and those were not intentionally micro-fabricated - they just turned out so because you needed lot of them and small. They ended up making nice small systems - not very small but small systems. And then there was another thread to this which was the whole notion of high-throughput screening which had a number of connections that tied together. One of them was just the need in industry to do lots and lots of experiments in parallel the acceptance of 96 ??? plate formats which was the first of these. And then the idea of parallel synthesis, combinatorial synthesis, parallel synthesis which came partly from Bruce Merrifield – he got the Nobel Prize for solid state synthesis of peptides - and partly from a bunch of people including, at least I give credit to, a man named Mario Geysen as being the first person to do combinatorial synthesis, parallel synthesis, on pins. They weren't terribly small but he had that notion. Out of that came the whole idea of very large-scale parallelism in synthesis which had a requirement for making things small which led to new requirements for small systems. It is an interesting area, the bio-area, both because it has had an important impact on genomics and drug discovery and also because it provides a bridge between these two areas of biology and materials science. This is where they come into contact.

AH : You have put together elements of techniques and ideas. I presume that funding structures have had impact on the history also ?

GW : Yes. Most of the funding for materials science in the US has come from DARPA. DARPA also got interested in the biological stuff in the mid-80s, maybe a little bit later than that. Their driving concern was with biological weapons - biological defense. The United States does not have an offensive program but it was clear that there was a potential problem there and then in the late 80s there was a Russian defector and then in the early 90s another, Ken Alabakoff(?), who spent a lot of time talking about what the Russian program had done. It was clear that the Russians had had a very very large program in biological weapons and it really bothered people. So there was a growing effort to think about how to build sensors and analytical systems, how does one put together a defensive program in this. That ended up being an important bridge between the materials community (which was the DARPA community) and the biological world. One of the things that DARPA does very well as that when it decides to go into an area to put in enough money for a sufficient period of time that it is actually worth people's effort to go and learn how to do that because they can run programs that make a difference. They get, I think, a lot of credit for building the biological component for micro-fluidics and then of course a very large fraction of soft lithography was funded by DARPA and their interest in that was largely new methods of circumventing the natural limits in photolithography for very high-density electronics. It has not in fact changed that - I mean these techniques are not used for high density electronics - but I think they are going to be the basis for low density low-cost electronics, the organic stuff. I think this whole area is one that DARPA gets the major credit for. Had DARPA not put the money in it would not have happened or it wouldn't have happened the way that it has. NIH has been very resistant to doing anything in this because NIH only does science, it doesn't develop tools. I think it is an enormous strategic mistake on their part but they have basically been parasitic on activities funded by other parts of the government or funded in industry, in start-ups, for the tools that they use and the biological community uses. Then of course there has been some work in the NSF and DoE but not big programs.

BBV : So do you see the contribution of your group as providing new tools for materials science ?

GW : The biggest contribution is to make the connection between physical organic chemistry and materials science - that is the idea that you can design molecules, or design matter by synthesis at the molecular level, and thereby influence macroscopic materials properties. The second is to put together a series of tools, particularly self-assembled monolayers and soft lithography and illustrations of the uses of these in microfluidics and particularly in bio which have caught people's attention. This is an interesting strategic decision : we decided at the very beginning that we were going to proselytize for the area, so we made a really big effort to have anyone who was interested. We invited them to the lab and tried to teach them everything that we knew. It is one of those interesting philosophical issues in science : when you have something that is new and interesting you either try to hold it close or you try to spread it as widely as possible, and we really made a big effort to spread it because I thought it was going to be very useful. Quite a large number of people would come for two-three days or a week over the course of time and then these people have gone out and started programs and then of course the graduate students come and learn how to do these things and they go off and start programs. So, the dissemination has been quite rapid, primarily because it is very easy to do. That is another philosophical issue : I like to do research that is really easy to do because other people can do it. If you want to have an impact on the community at large it is easier if you keep the bar low to people getting into the area rather than making the bar high. So, minimal capital investment.

BBV : And how much time do students need when they come to be trained in the techniques of self-assembly ?

GW : Two days.

BBV : Two days ? It is kitchen experiment !

GW : It is kitchen experiment. You take some wafer and you dip it and you pull down the stamp(?). That is not complicated. And stamping is literally no more difficult than putting a rubber solution on a rubber stamp and putting it down by hand and pulling it off and it's done. It obviously gets to be more complicated than that but you've got the basics at that point. There is a little issue there, which is : you say this is trivial, and in a sense it is trivial, but it is trivial because some very smart students spent a lot of time understanding these systems and figuring out which ones worked so well that they could not be made to fail. That is the criterion. The simplicity at the end is the result of a lot of hard thought along the way not just by us but by the whole group of people who was interested in self-assembly and related areas. The second thing is the tools and the third is the notion of self-assembly. Generally, organic chemistry has been largely concerned with making molecules by putting together covalent bonds and self-assembly is how you make materials through non-covalent interactions. So it is a switch in emphasis. We are certainly not the only ones who've worked on self-assembly but we have probably been more emphatic in making the case that it is a technique that can be used in materials science than other people who have been concerned with making structures in solution or how proteins fold or other things of that kind.

BBV : It is striking that other groups doing self-assembly have had biomimetic inspiration whereas in your group it was not a leading ...

GW : Well, we do biomimetic stuff. If you talk to some of the people around, Mila Boncheva, who I think with a little luck you will meet, has made this wonderful device. You basically have a string of something and you put this in suspension, it folds up and one part of it becomes a high-frequency ring oscillator and the other part becomes a shift register. It's quite intentionally patterned on the idea of protein folding so it is biomimetic in that sense. But the major issue is the generic problem, which is to understand molecular recognition in biology because if you want a single process in biology that is important it is the recognition of a ligand by an enzyme-active site, or whatever - that is the reductionist end of the working part of biology. There has been lots of work on that - and then self-assembly came in, as a result of two things : one was to try to model biological recognition and interestingly this has never really worked. There is an enormous amount of molecular recognition that has gone on in methylene chloride solution, but of course water doesn't go on in methylene chloride, so in organic solvents a lot of good work has gone on which has led to systems that are pretty efficient in molecular recognition. But noone has come really close to duplicating the efficiency of biological molecular recognition in water because we have to learn how to handle the hydrophobic effect and we don't know how to do that yet. So that is one theme. The second theme was the stuff that Jean-Marie Lehn, Cram, and Pedersen from DuPont got the Nobel Prize for, which was just understanding the crown ethers of the right size would wrap themselves around a sodium ion. That was not really molecular recognition, but it was self-assembly ... well ... Jean-Marie calls this supermolecular chemistry, so it is chemistry beyond molecules. It was an important first step in making the case that it isn't just making covalent bonds that's important but these events in which things recognize one another and get together without making covalent bonds are also important. So these two things came together in self-assembly. One virtue of this place is that students are very good and very independent, and the groups are big so that we can have biologists, chemical engineers, physicists, organic synthetic chemists, and materials scientists. That makes it much easier to think about putting biology and materials science together, or organic synthesis and microelectronics ; you know x and y, where x and y come from very different directions. It is a lot harder to do that in smaller groups.

AH : Do you think there is any purpose in doing history of science ?

GW : Oh yes. Understanding what this funny activity is of creation. Hang on, I'll be right back - this last question is important ...

History of science. If you look at history of science you can see where interesting things came from. Now, the question is, can one learn something from the activity, and I think the answer is yes. The question that comes up in this area is, is it sufficient just to put different research areas together in order for good things to happen, or do you have to have a brilliant conception ? No, I don't think in this case one needed a brilliant conception. It was putting things together - with some luck - self-assembled monolayers were an experimental observation, they were not a theoretical prediction confirmed by experiment. It still amazes me that soft lithography works as well as it did. In any event, one can ask where ideas came from, and from that point of view the history of science is an enormous contribution. The question which is never clear is, to what extent are there lessons that you can learn from one success or one failure that you can carry over into other areas ; and in particular : what is the mechanism by which whatever lessons you learn are transmitted to the people who are the ones who in principle would benefit most, who are the people just beginning their careers, but who are in general the least interested in listening because they are eager to get on with it. They have their own usually not very well-formed theories as to how to do things and it is based more on their own particular instinct. A lot of their instinct, in fact, turns out to be replication of the experience in graduate school. That is probably the least perceptible but longest lasting lesson of the graduate career, because people tend to do their research the way they learnt to do research which was the way their research director did research. That stylistic issue comes across. In a sense, one of the great sadnesses of science is to look at people at the age of 50 and realize they have spent their entire career working on their theses with minor variations on themes. It is not a happy outcome. What they learnt was, don't step too far out of this particular circle ; just sit there and fret away with this stuff. So, I think there is enormous opportunity for the history of science to be useful, and even predictive if one could figure out what to do with the information. As we made a big effort to teach people how to use soft lithography, I think all scientific enterprises, particularly with fields that move rapidly, which is what science does : it is always looking forward and almost never backward, one needs some clever way of figuring out what the short-form lessons are from what you do, what you have learnt. But I don't think the user will study things. A book which I think is a very interesting example of history of technology which has made a big difference is The Innovator's Dilemma. Have you read The Innovator's Dilemma ?

AH : I haven't read it.

GW : You should read The Innovator's Dilemma. It is by a guy named Christensen, who is somewhere here at Harvard or MIT. It's history - history meaning business school history, but it's close enough - and the question is : look around and you find big technology changes, and how do companies react to that ? And the answer is in general : incredibly badly. And this book has really caused people to think about how they run their technology programs (in companies) because the failures are so stark that as a big company person it really does not give you a lot of confidence that whatever you are doing is going to survive. One of the lessons in this is this : the mantra in the United States is listen to the voice of the customer ; the customer will tell you what you do. And one of Christiansen's lessons, loosely re-phrased is that if the field is technologically changing the thing that will kill you is to listen to the voice of the customer, because the customer never wants change - the customer has people trained in some technique, they've got capital investment and so on and so forth : the last thing in the world they want is change. So you listen to your very conservative customer and some little company who wants to take your customer away or create new customers, is going to zip around on the side. Now the interesting issue for you all is, you are doing all this stuff and my guess is that websites may be interesting for other historians of science but I don't think it will make any difference to scientists. So what you need is a nice short book which summarizes all of this in terms of lessons. What are the lessons that you can draw from this ? What has succeeded in what circumstances and why ? And what are the risks, and what has failed ? People hate failing. So look around and what are the failures, and what did they not do that prevented them from competing effectively ? I think if you think about history of science rather as the business school thinks about its analyses in terms of something that's branded in terms of suggestions for the next generation or the current generation of operators rather than sort of a passive observation it might have more impact. I don't know whether you care whether it has more impact or not.

BBV : We care about our impact.

AH : I care a lot.

BBV : Thank you very much !

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« Entretien avec George Whitesides », par Bernadette Bensaude-Vincent et Arne Hessenbruch, 28 janvier 2002 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article130.
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Entretien avec George Whiteside, par Bernadette Bensaude-Vincent et Arne Hessenbruch, 28 janvier 2002 : on history of organic chemistry and materials research and on the purpose of history of science.

Lieu : Prof. Whitesides' office at Harvard University

Support : enregistrement sur cassette

Transcription : Bernadette Bensaude-Vincent et Arne Heseenbruch

Edition en ligne : Sophie Jourdin

HIRSCH Peter, 2002-12-12

Sophie Jourdin — 2011-11-04T14:03:56Z

Professor Sir Peter Hirsch.

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BERNADETTE BENSAUDE-VINCENT (BBV) : Could you tell me about how metallurgy developed in Oxford and how it grew into Materials Science ?

PETER HIRSCH (PH) : Let me first say a few words about the way I see the early developments of Materials Science in the UK. There were various trends that came together after the War. First of all there was Professor Nevill Mott in Bristol, developing Solid State Physics. His interests included inter alia defects and how they influence properties of materials. He had important activities on properties related to point defects and on the photographic effect. In the course of these studies they also developed techniques for visualizing dislocations. The group included Charles Frank, a physical chemist by training who was a material scientist par excellence. He developed a theory of crystal growth. Then there was Nabarro who worked on dislocations. So in Bristol they worked on defects, dislocations, crystal growth, the photographic effect, and also optical properties of crystals.

BBV : Where were they based ?

PH : In the Physics department at Bristol University. It was Solid State Physics. The electron theory of metals was developed there too. And Jacques Friedel was there for some time. In my opinion Solid State Physics opened the way to Materials Science. In parallel with this there was the group in the Metallurgy Department in Birmingham, lead by Alan Cottrell. He is much more of a materials scientist than I am. He was subsequently instrumental in developing Materials Science in Cambridge. His activity in Birmingham was very important because his group attempted to explain mechanical properties in terms of disclocation theory. And the third trend was what happened here in Oxford through Hume-Rothery's classic work on electron phases of alloys. He stimulated work on electron theory of metals and alloys in Physics Departments elsewhere. He was trained as a chemist.

BBV : So it came out of these three trends ?

PH : These are the main three. I may be unfair to other groups but these were the most influential groups.
There was some Metal Physics going on in the Cavendish Laboratory after the war. Bragg, who was Head of Department was of course an X-Ray crystallographer. In order to understand the intensities of diffraction spots on an X-Ray diffraction photograph, it had to be assumed that the crystals were not perfect, i.e. that crystals consisted of mosaic blocks. This was based on a theory by Darwin (1914) of the intensities of diffracted X Rays. Bragg published a note in the 1940s on the relationship between strength and particle size (mosaic blocks) in crystals. There were two groups in the Cavendish in the Metal Physics field when I came in 1946. One was Bragg's little group which developed the bubble-model, typical of Bragg's simple but brilliant ideas. Another group was Orowan's Metal Physics group which studied plasticity, fracture, creep, those sorts of topics.

BBV : It is in the Cavendish Laboratory that you started your career, isn't ?

PH : It was 1946 when I joined and there were several activities. My own work started from Bragg's interest in work hardening (when you deform a metal it becomes stronger). I actually went into the Crystallography Department of the Cavendish to work on a PhD problem that Bragg gave me. It was conceptually very simple. If you take a metal and work it, does it break up into smaller blocks ? Bragg always had very simple and brilliant ideas. If the crystal breaks up into smaller blocks (subgrains) the diffraction pattern consists of individual spots from each little subgrain. If you make the beam small enough you illuminate such a small number that you will get a few spots on the diffraction ring, whereas, with too large a beam diameter you get a continuous ring due to overlapping spots. You can count the spots (on discontinuous rings) and deduce the size of the particles. That was the project. It did actually work for heavily cold worked aluminium. We derived a particle size of 2 microns. By the time we managed to do all this by X ray diffraction, Bragg had lost interest in it. He did not actually supervise me. Bragg was interested in proteins at that point. My formal supervisor was W.H. Taylor who was head of the Crystallography Department. His interest was the structure of minerals.

BBV : When you worked in Cambridge did you consider yourself as a crystallographer ?

PH : I was a physicist working in a department of crystallography. In those days most conventional crystallographers determined crystal structures. I was one of the relatively few people not doing that.
By the time we found that cold worked aluminium breaks into subgrains, Heidenreich at the Bell Laboratories published the first pictures of metals by Transmission Electron Microscopy (TEM). He observed directly the little subgrains in heavily beaten aluminium foil. That depressed us very much because we needed exposures of many hours for our x-ray diffraction photographs, while he had a ten second exposure with his electron microscope. So we went into this field of TEM and finally we saw individual dislocations. This had a big impact because there were many metallurgists who did not believe in dislocations, who considered them as figments of the imagination of solid state physicists working out theories in tremendous detail without much supporting experimental evidence. With our technique you could see dislocations directly and see them move. And we made movies. I remember showing a movie at MIT to Bert Warren who was a well-known X Ray crystallographer. His comment was symptomatic of many metallurgists. Seing is believing. We converted people.

BBV : In terms of institutions could you describe the shift from Metallurgy to Materials departments ?

PH : There were many Metallurgy departments in this country : Sheffield, Birmingham, Imperial College, to mention a few. The activities of the groups that I mentioned gave an impetus. But an important impetus came from the United States. Bill Baker and Herbert Holloman in particular had this vision of multidisciplinary activities leading to the development of better materials, whiskers, ceramics etc.. An enormous amount of money was spent at General Electric, and Bell Telephone and the Ford Motor Company. When Alan Cottrell became Professor in Cambridge that was the real beginning of an institutional effort to develop Materials Science in this country. In my opinion that was the defining moment. Alan Cottrell left Birmingham in 1955 and went to work at the Atomic Energy Authority at Harwell where he worked on uranium and materials for nuclear reactors. Then he became Goldsmith Professor of Metallurgy in Cambridge in 1958. He started projects on ceramics and composite materials. Tony Kelly joined him to work in these areas. Alan Cottrell ‘s interest in composite materials probably stemmed partly from activities in the US but mainly from his own views on strong materials. He also supported work on superconductors. His initiative to work on different types of materials was probably the beginning of the shift from metallurgy to materials science in Universities in this country.

BBV : Could you tell something about the implementation of Materials Science here in Oxford ?

PH : The department of Metallurgy and an Honour School in Metallurgy were started by the University in 1957. Jack Christian wrote a paper on the early history (Materials World, April1997) when the department celebrated its 40th anniversary. You see from this that Hume-Rothery started as a chemist and worked in the Inorganic Chemistry Department. But he was interested in metallic phases. The idea of a separate department arose gradually. Jack Christian was appointed as demonstrator in 1951 and initially lectured on metallurgical topics to chemists. Metallography was a supplementary subject in the Chemistry Honour School. Then the Pressed Steel Company at Oxford established a readership in metallurgy named after George Kelley. Hume-Rothery became the first George Kelley reader in 1954. Jack Christian was appointed lecturer in 1955, then John Martin came from Cambridge and joined in 1957, followed by Angus Hellawell. There was a move to increase the Engineering School and to develop a Department of Metallurgy. Francis Simon who was professor of physics here was keen to establish something on the lines of the Laboratory for the Study of Metals in Chicago, which was famous in those days. Chicago was a research institute, not a teaching department, just a research institute for postgraduates. This is what Simon had in mind for Oxford. However, the industrial advisors expressed the view that we needed to educate metallurgists to go into industry. British industry wanted a teaching department. Monty Finniston, who was at the time the head of the metallurgy division at AERE Harwell and later became chairman of British Steel, made approaches to the Wolfson Foundation for financial support. The result was the establishement of the Isaac Wolfson Chair in Metallurgy which Hume-Rothery held until his retirement in 1966.
At the same time the condition that the Wolfson foundation made for giving the money for the Chair was that the University Grants Committee, an organization distributing the money from the Department of Education to the Universities, should provide the funds for the building. Funds were provided by the University Grants Committee and the building was opened in 1959. Initially the Honour School was a Joint Honour School in Chemistry and Metallurgy, which subsequently became Metallurgy. There is an interesting quote in Jack Christian's paper which indicates the University's unease with technology at that time. The Honour School should teach « no more technology than is involved in the degree courses of chemistry and physics » and it stated that « the man who has studied pure science at a university can take up technology on entering industry much more easily than one who has studied technology can later take up the pure science which may be required for his work ». It was still quite difficult to really expand engineering and to get a proper engineering metallurgy course at that time. The research that was going on here was on alloy phases (Hume-Rothery's research) ; John Martin worked on mechanical properties of alloys ; Angus Hellawell worked on solidification studies ; Jack Christian worked on phase transformations - the martensitic transformations - of metals and alloys, and also on plastic deformation of body centred cubic metals. So that was the development of metallurgy in Oxford before 1966. Clearly this department was a metallurgy department rather than a materials department. But Hume-Rothery's work was influential in encouraging solid state physicists to become interested in metals. He stimulated the understanding of the structures of metals and alloys on the basis of the fundamental electron theory of metals. He empirically developed some structure rules. He hoped that electron theory of metals would enable the prediction of the structures of metals and alloys and appointed a theoretical chemist, Simon Altmann, to work in this area.

BBV : And then you came in this Metallurgy department. Why did you move from Cambridge to Oxford ?

PH : I came in 1966. I was a physicist who had worked on electron microscopy of defects in materials. I had the opportunity to take a Cambridge chair or an Oxford chair. I decided to go to Oxford for two reasons. 1) I had been in Cambridge quite a long time (23 years) and a change opens new vistas. 2) The challenge was much greater here and my own predilection was always for building things up. The Cambridge Metallurgy department was a large and successful department built up by Alan Cottrell. In Oxford there was really a nucleus of a department (a distinguished one) and in principle one could do a job to build it up.
I had already built up a large research group in the Cavendish in Cambridge. When Bragg switched his interests to proteins (Perutz, Kendrew et al) Orowan left and went to MIT. I don't know the details but my impression is that Bragg did not work hard enough to get Orowan a senior permanent job. So the Metal Physics group in Cambridge folded up. Bragg's own little group folded up too. We made a significant effort to set up a new Metal Physics group at the Cavendish. The vision behind this was : We now had a technique to enable us to actually see with the TEM what is going on inside metals and one could see the defect distribution after deformation or irradiation of the material. One could then determine in principle what the properties of the materials were. That was the Holy Grail. There were three steps : 1) to try to understand the properties of the defects and how they interacted ; 2) to try understand how they control the macroscopic properties ; 3) if one understood the basic relation between defects and properties then one could eventually go further and predict what processing should be done to optimise properties. That was the vision but while we were successful in the first step, there was only limited success in the second step, and we never got as far as the third step.
When I came to Oxford, my aim was to get this technique of TEM - to see what goes on in the materials - transferred to a metallurgy/materials department. I wanted to get it closer to applications to « real » materials. Whereas physicists work on models, - on pure copper for instance, a metallurgy department should be looking at materials of interest technologically, such as alloys that are much closer to practical needs. My aim was to apply TEM to technologically interesting materials, real materials rather than the model materials that we looked at in Cambridge.
When I got here I did attempt to build up Materials Science. Right from the beginning my aim was to shift from metallurgy to materials science which should cover all kinds of materials and applications.

BBV : Where did this project come from ?

PH : There was no model course. We had to build this up incrementally. When I first came the University provided three new permanent posts, very generously. One was for Professor Whelan, to establish the electron microscopy group. One went to John Hunt, a solidification expert who had worked at Harwell and Bell Laboratories ; and another one was for Geoffrey Groves who worked on ceramics. Gradually we built up a Materials Department by securing more appointments. You have to realize that when I came in 1966 the number of staff was very small (4 faculty plus the Professor).The course developed gradually and changed from metallurgy to materials science. In the early years a considerable part of the teaching was carried out by research assistants or fellows supported on research grants or fellowships. The research activities were built up first, and the research groups then helped in the teaching of the Honour School.

BBV : When did you officially change the name of the department ?

PH : That was much later, 1990. The name of the Honour School was changed to Metallurgy and Science of Materials in1969 (The University would not accept "Materials Science" because Materials was not an adjective !).

BBV : Did you appoint chemists as well ?

PH : We didn't appoint chemists to teaching posts. We appointed metallurgists and physicists. But we did appoint a chemist to a research post in the department, in high resolution electron microscopy. When I retired in 1992 the department consisted mainly of metallurgists or materials scientists and physicists or ex-physicists. We appointed inter alia people who had expertise in semiconductors, superconductors, magnetic materials, materials processing, corrosion. Gradually we extended the scope of the courses in the department. The one sticking point was polymers. For a very long time we could not get a good polymer scientist. It has changed now. We now have two polymer scientists.

BBV : Did you have contacts with John Goodenough who came to the chemistry department in 1973 ?

PH : We did have contacts but we probably did not make the best of the opportunity. In this department we were more interested in the effect of microstructure on materials, metals, ceramics, semiconductors, superconductors, magnetic materials etc., rather than e.g. in the intrinsic magnetic properties of perovskites and other materials. Our interests were not sufficiently close. We became a Materials Department in that we were concerned with the effects of microstructure on properties of a wide range of materials of technological interest and with the effects of defects on devices. The work on superconductors was initially on low temperature superconductors, but later on high temperature superconductors, and the more recent studies focused on processing. There was some interaction with the Inorganic Chemistry Laboratory on electron microscopy of catalysts and superconductors.

BBV : Did you keep a close link between courses and research in the department ?

PH : Yes. We started as a metallurgy department. We built up a number of research groups, and the expertise in some of these, e.g. semiconductor and magnetic materials, enabled us to teach courses on these topics and broaden the curriculum to Materials Science. At some point we had a group working on cements, and this too led to a course in the Honour School. And there were always undergraduate and postgraduate courses on materials characterisation, where we had particular strengths. In the 1980s, I became more interested in the output end, in getting closer to the engineers.

BBV : Did you train students in engineering ?

PH : The engineers had their own faculty to teach materials to Engineers. But we did some teaching for them, and over some years they taught polymers for us. In the mid 1980s we started a joint course with the Engineers on Electronic and Structural Materials Engineering, changed to Engineering and Materials in 1992. This led to closer collaboration with the Engineers in teaching and research.

BBV : Did you also have contacts with the nuclear physics department in Oxford ?

PH : The only contact we had with the Nuclear Physics Laboratory in Oxford was on their proton microprobe, a materials characterisation tool, and fairly recently this activity was transferred to our department.

We had a lot of contacts with Harwell. From 1973 onwards I got very much involved with the study of the integrity of pressurized water reactors through the Marshall Committee. From 1982 to 1984 I became part-time chairman of the Atomic Energy Authority. This period had a strong influence on me. I felt the need to produce materials engineers, not only materials scientists. I learned during my period with the Atomic Energy Authority that the education of engineers in materials tended to be relatively poor. And this could result in inappropriate component design or manufacture. These problems sometimes led to costly mistakes. In order to develop a joint activity between engineers and metallurgists we got some support from the engineering department. To cut a long and difficult story short, we took an opportunity which presented itself around that time in the form of additional funding for engineering courses from the Government to start a course on Electronic and Structural Materials Engineering.

BBV : Was it in the 1980s ?

PH : Yes.

BBV : Did you then feel the need to add « engineering » in the name of the department on the lines of the departments in US universities that are called Materials Science and Engineering with an emphasis on the E of Engineering ?

PH : What happened here is that we developed a multiplicity of courses to provide more options for the undergraduates to increase our intake. The courses were Metallurgy and the Science of Materials, then Metallurgy, Economics and Management (1979), and finally Engineering and Materials. There is close collaboration between us and engineering through the teaching and contacts in research. This depends on individual contacts of course. In the 1980s we set up with the Engineers the Oxford Centre for Advanced Materials and Composites (OCAMAC) to foster collaborative research and contacts with industry. There is now also strong collaboration with people in chemistry and physics on a number of research programmes. We have become much more interdisciplinary, if you like. We have always considered ourselves as a bridge between the Science and Engineering Departments, with contacts with both. The fact that Physical Science and Engineering are all part of the same faculty in Oxford is advantageous to us. We did consider changing the name of the Department to Materials Science and Engineering - but that was unacceptable to the Engineers who considered Materials Engineering to be their responsibility. So we decided to change the name in 1990 to "Department of Materials".

BBV : It seems that your story is quite different from that of the US materials departments.

PH : I think that it is different ; you are quite right. Here the initiative to have Materials Departments came from academics, whereas in the US the development was led by Industry, and industrialists promoted Materials Science in Universities. (This does not mean that no materials science was going on in industry in the UK - e.g. the carbon fiber work at Farnborough.) I think it started in Cambridge first. We came along in the late 1960s. By that time there were materials science activities going on in many departments, at Imperial College and Birmingham, for instance. We could not claim to have inspired Materials science in the UK. We came along and did our own brand. There were many departments, but they were on a small scale. Concerning the definition of Materials Science I am with Merton Flemings. Structure, properties, processing, performance/application. I think it is the engineering applications that are fundamental. The philosophy of the department here was to get theoretical and practical people together. People able to develop models with people who really know what applications are important. And industrial links were fostered. It is still the philosophy today, even more so. In the last few years after my retirement the department has gone from strength to strength in that direction. There is now another site in Begbroke, five miles away from Oxford centre. It provides opportunities for collaborative research between the Department and Industry.

BBV : Where did the money come from ?

PH : The funding for work in the department came partly from the University, the Research Council and Industry. Some from charitable foundations, e.g. for building expansions. We had a large budget from the Research Council. That is another important aspect, somewhat similar to the US picture.

It is difficult to attract undergraduates to read Materials Science and Metallurgy. Enormous efforts have been spent on attracting more undergraduates, most of them not very successful. (But a recent appointment of a Schools Liaison Officer seems to be effective.) Materials Science is not a school subject, although elements are introduced into some of the school examination papers e.g. the physics curriculum. The number of courses and options that we offer in Oxford has helped a bit but it remains a problem. Some small departments in the UK were able to survive because they had a large research activity (supported on non-University funds) compared to the undergraduate activities. But in the UK as a whole some Materials Departments have closed or have been amalgamated with Engineering Departments. The change of name of department from Metallurgy to Materials does not only reflect the change in content of the courses. It is also pragmatic because metallurgy has an old-fashion ring about it and materials science is a much broader subject likely to attract more students. The image of materials for computers, aeroplanes and cars is more exciting than that of dirty blast furnaces in the steel industry.

BBV : What would you say about multidisciplinarity in the development of this department ? More specifically could you compare the situation here in Oxford with this diagram published by the National Academy of Science in 1969 with a hard core in mathematics physics and chemistry and applications around ?

PH : I would agree with this : mathematics, physics and chemistry are basic inputs in Materials Science with applications in ceramics, polymers, and so on. But in these days I would include materials for medical applications. There is somebody in this department working on biomedical materials for implants. There is also a large group in Cambridge. There is a big scope for materials in medicine, particularly for prostheses.

BBV : Finally would you consider yourself today more as a physicist or as a material scientist ?

PH : I think I am physicist who « saw the light ». True physicists would no longer consider me as a physicist. I consider myself as a materials scientist because my interest is in the effect of microstructure on the properties of materials. I am interested in quite complex materials, with potential applications e.g. high temperature intermetallics, and in modelling their complex mechanical properties. I ended up as a materials scientist. But there are materials scientists who would consider me to be a rather theoretical materials scientist. In the later years of my conversion I supported and promoted materials processing in the department although it took me rather a long time to get to this view, to appreciate the importance of this field, and to realise the need and potential for modelling.

BBV : What is your concept of materials science ?

PH : I am close to Merton Flemings's concept. To me materials science is an enabling science. We study material composition, structure, properties and processing for applications in engineering. There is now a strong group on processing here. Not only casting but various kinds of processing like spray forming, coating, making magnetic and superconductor devices etc. There are also two lecturers working on polymers now.

BBV : Does polymer synthesis now belong to Materials Science ?

PH : Polymer processing and modelling properties belong to materials science, but synthesis of new kinds of polymers - I doubt if this is a proper activity for a materials department, although it would be quite appropriate as a joint research activity with Chemistry. That would be my view for what it is worth. But composition, structure, properties, performance, Merton Fleming's picture, defines Materials Science.

BBV : What about the recent addition of end-users to this picture ?

PH : Yes end-users are important but I would consider that this links in with performance. The interaction with industry is important. Quite apart from the problem of funding it is vital for materials science, as an enabling science.

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« Entretien avec Peter Hirsch », par Bernadette Bensaude-Vincent, 12 décembre 2002 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article126.
—

Entretien avec Peter Hirsch, par Bernadette Bensaude-Vincent, 12 décembre 2002

Lieu : Materials Department, Oxford University

Support : enregistrement non précisé

Transcription : Bernadette Bensaude-Vincent

Edition en ligne : Sophie Jourdin

HIRAO Kazuyuki, 2002-08-29

Sophie Jourdin — 2011-11-04T13:08:55Z

Kazuyuki Hirao.

—

HERVE ARRIBART (HA) : In which discipline did you take your degree and your Ph.D.?

KAZUYUKI HIRAO (KH) : I was trained in Inorganic Chemistry.

BERNADETTE BENSAUDE-VINCENT (BBV) : Why did you decide to go into Glass Science ?

KH : Well, you know, the Chemistry Department of Kyoto University is very old, 100 years old. When I had to select a laboratory, I was interested in inorganic chemistry. I belonged to the Chemistry Department but only one division of chemistry was Glass or Ceramics related to inorganic chemistry.

BBV : Did you publish books in inorganic chemistry ?

KH : Yes, I published two textbooks on Inorganic Chemistry intended for undergraduates. One of the textbooks was translated but another one I wrote myself in Japanese.

BBV : Do you have to teach inorganic chemistry ?

KH : Yes at the undergraduate level.

BBV : And do you have to teach a course in Materials Science ?

KH : Yes I have 3 courses a week : one of them is Glass Science, the second is Advanced Materials, and the 3rd one is Inorganic Chemistry. Inorganic Chemistry for undergraduate students, Glass science and Advanced Materials for graduate students.

BBV : There is no department of Materials Science at Kyoto University ?

KH : Materials Science partly belongs to chemistry. My department is called Department of Materials Chemistry. But Materials also belongs to Metallurgy. They have a department of Materials Science which is totally separated from us. We have no common class between Materials Science for chemists and Materials Science for metallurgy. We have to collaborate in the future. The Department of Materials Science also belongs to the Department of Mechanics. Chemistry and Mechanics are totally different. Polymer Chemistry is also separated. We still have to build up the new class of Materials Science. In Japanese universities, it is not usual to have interdisciplinary Materials Centers. It is usually divided. It is not good for research. Because equipment is shared.

HA : What kind of instruments ?

KH : TEM, SEM, X Ray, spectroscopy. At least in nanotechnology we ignore the boundaries between polymer science, metals, ceramics and glass. It will be possible to develop the new materials perspective.

BBV : Do you think that this traditional university system prevents you from doing Materials Science ?

KH : It is difficult to change. If you want to change anything, you will have to obtain agreements from all the professors in our departments. University professors are very conservative.

HA : Still, Professor Soga did endeavor to change the system while he was here.

KH : Yes, but in Japan if one single professor is against the change, then there will be no change at all. We don't usually have a majority decision making system.

BBV : Are the students more attracted by Materials Science in general or by Chemistry and Physics ?

KH : The entrance examination is about Industrial Chemistry. Almost 250 students are admitted. After one year, in the 2nd grade, they will be distributed into three different courses. Three classes divided mechanically. In the 4th grade they chose to enter into one the laboratories of the department. Four graduate students choose to enter in my laboratory every year. Kyoto University is a very big university. We have almost 47 chemistry professors for 250 students. 150 graduate students. Two Nobel Prizes came out from this department. It is a prestigious department.

HA : Could we come back to your PhD subject ? How did you choose it ? Was it Professor Soga who proposed it ?

KH : Yes it was about Glass Science. Thermal properties of glass.

HA : From your list of publications I can see that you have worked on many, many fieldswhile working in Professor Soga's laboratory.

KH : Yes I have been mainly interested in computer simulation of making glass structure and predicting optical properties of glass. I started computer simulation early in the 1980s. It was too early. The computer capacity was very small in the 1980s. Now we have a big project on computer simulation program and we get $5 million over five years from the government for it. Owing to the progress of computers, we can make glass structure containing 10,000 atoms.

HA : Then why did you move to non-linear optics instead of mechanical properties or low temperature behavior ?

KH : It is a good point. One major advantage of glass is transparency. Its major disadvantage is brittleness. Optical fibers are a very important because electrical wires are very limited in speed.

HA : So by the end of the 1980s you guessed that the future of glass for a large application would be optical glasses.

KH : Now we are very lucky. We are also interested in the mechanical properties of glass at the nanolevel. We are dealing with elimination of the nanobubbles. It is very important for industrial companies.

HA : So you got in to the glass making process ?

KH : Yes.

BBV : Was it industrial demand that prompted you to work on optical properties in the 1980s ? Or was it your own initiative, your choice ?

KH : In this period the optical properties were not important for glass industry. Now many glass companies are interested. So now we have a lot of industrial contacts. Before next year we intend to produce 3 commercial optical glasses called photonic glasses. For this, we need connections with venture business.

BBV : Do you mean that you conducted all these researches on optical properties without industrial support ?

KH : No, only in the beginning. Now we get a lot of industrial support. But now I get a lot of budgets from three kinds of government projects, not only from industry. We have 3 projects. One is computer simulation. One is on photoactive glass in cooperation with foreign countries. So we have a lot of post-docs in my laboratory. The third one is the nanoglass project.

HA : Could you tell us about this nanoglass project ?

KH : The government launched a nanotech program that covers a variety of projects : nanometals , nanopolymers, carbon nanotubes, nanocoatings, nanoparticles, nanosimulation and the nanoglass project. For the latter, we get $30 million for 5 years approximately.

HA : How do you spend this amount of money.

KH : Most people involved in the glass project are coming from industry, from Asahi Glass, Hoya, Nippon Electric Glass, Central Glass, Okamoto Glass, Nippon Yamamura Glass, Hitachi, ... 11 companies sent us 15 researchers whose salaries are paid by the project.

HA : How many people are working in your nanoglass project ?

KH : 100 people including the supporters. They join in Tsukuba consortium, from Osaka Institute and several university professors also support us.We have some large equipment.

HA : When did this project start ?

KH : We had a preliminary year and the project itself started in 2001.We have got a number of results. For instance CVD deposition. We also succeed in making very low optical loss glasses. We have reached 0.005dB/cm. This glass will be very useful for making waveguides. In Tsukuba we use two kinds of femtosecond lasers working at 1 kHz and 200 kHz. By using these femtosecond lasers, we not only write in waveguides but also we make crystals from glass, for example silicon crystals from amorphous silica.

HA : Last time you mentioned that you also have a laboratory in China working on crystal growth.

KH : That is right. And we have also made a lot of semiconductors, single crystals in glasses by using this material and we made photonic crystals, which can be used as optical filters.

HA : Where does the money for this nanoglass project come from ?

KH : From NEDO. It is part of METI (Ministry of Economy, Trade and Industry). No connection with AIST although METI also supports AIST. We also made a very tough glass whose strength is very high, 2 times that of standard glass. With the femtosecond laser we made very small dots, nanosize dots, that stop the cracks. We have already succeed.

HA : Was it enough to make these tiny holes on the surface ?

KH : They are under the surface. Also by using the interference technique we have made a lot of dots.

HA : I understand, it is beautiful glass but too costly for bottle makers.

KH : Of course it is not for bottle makers ! Also we have found a cheap process to make AWG (array wave-guide grating) by using the femtosecond laser. AWG are very useful for optical telecommunications. Until now, they were very expensive to make. We also managed to make a nanoglass thin film for CD. The storage medium can be a cobalt oxide-based glass, for example. When we apply a nanoglass coating on this recording material the blue beam is shrinked to ¼. This is a lens effect. We have now this optical disk standardized by Hitachi. So you know that Shuji Nakamura ; a Japanese researcher, has discovered the blue laser diode. In my case by using this blue laser diode, the recording capacity is approximately increased by a factor 4, because the beam is much smaller. And in the field of optoelectronics, we have made 3 dimensional devices including both electrical and optical circuits. We use gold containing glasses that crystallize under laser beam. Three dimensional wires can be obtained, together with optical waveguides in the same device.

HA : So this program seems to be essentially telecommunication oriented.

KH : Yes NEDO asked us to make such devices. Otherwise they would cut the financial support.

BBV : You mean that the budget is according to your practical results.

KH : Yes.

BBV : What kind of connections do you have with venture business ?

KH : For optical properties we have to make such connections. Otherwise we could not do it on university money or government money. Venture business have a lot of demands in optical properties of glasses. For instance some fibermakers make lenses inside optical fibers. With my technique of femtosecond laser we can make lense in fiber. There are many such innovations of interest for business, although optical properties are not directly related to optical devices.

BBV : Do you mean that you only do research and no development ?

KH : Optical properties are synchronized with optical devices. There is no linear sequence from optical properties to technical devices, from basic research to applied science then development. We have to work in synergy.

HA : So do you consider yourself as a materials scientist because you are dealing with devices ?

KH : Yes we have to make connections with venture business and industry. For doing this kind of research we have to build a wide network. So many venture businesses are connected with me and they are eager to be.

HA : Where does the money come from ? From big industrial companies ?

KH : So far my devices did not cost much. If one day we have to develop a costly device, the Japanese governement is able to support us immediately, at least for two or 3 years. The Japanese governement is encouraging this kind of cooperation.

HA : Do you also collaborate with foreign companies ?

KH : With Schott in Germany. They have sent a researcher here. And Corning is also willing to collaborate. In the USA glass professors are not so many in optical devices. Here we have more than 50 professors of Glass Science

BBV : Do you send students to the USA ?

KH : Not right now.

HA : Where do you locate the leading centers in your field ?

KH : I guess Osaka is the center. Glass science originated in Osaka National Center.

HA : You told me last year that you run many laboratories. How many ?

KH : I have 6 laboratories including one in China, one in Osaka, one Tsukuba ... 300 people altogether. There are autonomous and eager to make things because optical devices is a very promising field. So I don't have to be continuously behind them. There are so many things to do such as inkjet using semiconducting cadmium selenide nanoparticles. The color changes depending on particle size.

HA : This is not glass. Is it ?

KH : Yes it is, because nanoparticle CdSe particles are made in micelles and encapsuled by glass using sol-gel chemistry. The fluorescent yield increases nearly 10times using these nanoparticles. Silica sol-gel coating is necessary ; otherwise the semiconductor particles aggregate to each other. Encapsulated particles are then deposited by inkjet to make displays. We do this development by collaborating with venture business.

BBV : So you seem to work as a partner of venture business, as a manager of projects rather than as a traditional scientist supplying science for applications downstream.

KH : Yes my aim is really to make optical devices. This is what we have to do. We teach Glass Science. But in laboratory research we have to make devices. Traditional professors are not interested in devices ; I am. But you see, in Japan I don't have to move to an industrial company to make such devices.

BBV : Is it part of your obligations as a university professor to make devices ?

KH : No, teaching is the only obligation. We just have to teach and take care of the students.

BBV : Does the university system recognize your devices ?

KH : Yes now the government recognizes patents.

HA : So you feel that you are in a better position at the university because you have the freedom of choosing your topics of research and you have the money that you need for them.

KH : Yes I am very lucky.

BBV : How do you select your research projects ?

KH : The keywords are glass and optics. We have a lot of choices. One criterium is to use the femtosecond laser.

HA : You mean that you can use it to change glass composition ?

KH : If we use samarium doped glasses we can change the samarium3+ to samarium2+ with the femtosecond laser. So glass composition is very important for me. Not just to make new glasses and measure their optical properties. If we make a new glass it is to make a new device by using a new technique. We also made electrical lithography by plasma etching for nanodevices, in Osaka.

HA : On our webpage you also mention that you are working on hybrid materials.

KH : Yes usually at the macroscale, it is difficult to combine organic and inorganic components. Nanohybrids work better by using chemical reactions with micelles. Professor Tetsuo Yazawa at Himeji Institute of Technology University made a lot of nanohybrids that can be used for gas filters, for membranes, solid sensors and solid electrolytes. Conductivity is very high in the nanohybrids. Both electronic and ionic conductivities. And hybrids are also useful for glass capsules for drug delivery. So we started that kind of research on hybrids within the nanoglass project.

BBV : Do you try to compete with other materials in your nanoglass project ?

KH : No, glass offers unique advantages. We can overcome polymers. Glass is the only transparent material even at the nanoscale. I forgot ! Athermal glass is very important. We achieved athermal glass-ceramics we have to apply pressure to control the size of the nanoparticles and the growth. So nanoglass is unique and very useful.

HA : I can see that your project works very well. But do you remember any failure in your research career ? It is also instructive for our project on the history of Materials Science.

KH : For the Photoncraft project we are at the middle point so we have to submit. The nanoglass project started one year ago. We have to make an effort, otherwise budget might be cut.

HA : This morning Professor Soga told us that he considers himself as an educator rather than as a glass scientist. Is teaching and training also important for you ?

KH : You cannot separate teaching and research. Education and laboratory work together. In the field of glass, just making optical devices is a good education, a good training. Now we are training a number of students through the nanoglass project.

BBV : Do you mean that the nanoglass project is in itself a kind of training ?

KH : Yes, for graduate students. When I present the results of our nanoglass project to company presidents, they are essentially grateful for our work as educators because we train the researchers from industrial companies. Helping each other is very important.

HA : Does it mean that you are no longer interested in basic research and basic education ?

KH : No. Presently I am making devices but maybe in a few years I write a new textbook of glass science because they are so many new glasses that all conventional glasses are obsolete. This textbook should be written in English.

BBV : You want to write a textbook of Glass Science, not of Materials Science in general ? Are there any Japanese textbooks of Materials Science ?

KH : Yes and we had written one.

BBV : One final question : Do you see differences in the research styles of various countries ?

KH : In Europe originality is important. Here it is rather collaboration and harmony. We are more modest, more humble. Collaborations, mutual help and mutual learning, Interdiscipinary philosophy is my project aim.

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Pour citer l'entretien :

« Entretien avec Kazuyuki Hirao », par Bernadette Bensaude-Vincent et Hervé Arribart, 29 aout 2002 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article125.

—

Entretien avec Kazuyuki Hirao, par Bernadette Bensaude-Vincent et Hervé Arribart, 29 aout 2002

Lieu : Department of Materials Chemistry, Kyoto University

Support : enregistrement non précisé

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

LIVAGE Jacques, 2001-01-04

Sophie Jourdin — 2011-10-28T11:49:52Z

Jacques Livage

Bernadette BENSAUDE-VINCENT (BBV) : Quel itinéraire vous a conduit de vos débuts dans un laboratoire de chimie des hautes températures à la « chimie douce » à température ambiante ? de la chimie du solide aux sol-gels ?

Jacques LIVAGE (JL) : D'abord mon origine n'est pas le laboratoire Collongues. Je l'ai rejoint dix ans après le début de ma thèse et à la suite d'un post-doc à Oxford. Après une formation de chimiste à l'Ecole de Chimie de Paris, j'ai préparé une thèse sur la zircone obtenue par précipitation. Ensuite je suis allé à Oxford pour étudier la résonance paramagnétique électronique - ce qui est un thème de physique. C'est en revenant que j'ai rejoint le laboratoire de Collongues.

BBV : En quelle année ?

JL : Je pense que c'était vers 1972 quand Collongues est venu s'installer à l'Ecole de chimie de Paris. J'étais sur place. Je ne connaissais pas a priori l'historique du laboratoire de Collongues. Alors pourquoi ai-je travaillé sur la chimie douce ? Il y a deux raisons.

- Cela tient à une raison personnelle. Au retour d'Oxford j'ai été journaliste scientifique à l'Usine nouvelle, à La recherche et journal Le Monde. Et c'est une idée que j'avais et que j'ai développée dans un article du Monde.
- La deuxième raison est opportuniste. Quand je suis arrivé chez Collongues, j'avais un contrat avec Kodak pour la réalisation de dorsales antistatiques qui étaient des oxydes de vanadium ayant des propriétés électriques. Il s'est avéré que pour pouvoir déposer cet oxyde, il était très commode de fabriquer des gels. C'est pourquoi je suis passé des hautes températures qui ordinairement servent à déposer des couches minces à la chimie douce. C'est donc une problématique industrielle qui a fait que je suis passé d'un thème haute-température à la chimie à température ambiante.

BBV : En arrivant chez Collongues, travailliez-vous sur contrat industriel ?

JL : Oui, il s'agissait d'un contrat Kodak qui portait sur des problèmes de mobilité électronique et la RPE que j'avais étudiée à Oxford est adaptée à l'étude des électrons. Donc j'avais une technique adaptée au problème.

BBV : Avez-vous pris des brevets ?

JL : Il y a eu des brevets pris. Malheureusement Kodak a pris les brevets sans nous en parler. Cela ne s'est pas très bien passé avec Kodak. Mais c'est un procédé qui a été commercialisé et qui est toujours utilisé actuellement. Toutes les pellicules que vous achetez sont faites de cette façon.

BBV : Avez vous continué dans ce domaine ?

JL : Oui on a continué, sans Kodak. Du moins sans Kodak France, en travaillant parfois avec Kodak Etats-Unis. C'est ce sujet là qui m'a fait découvrir les gels que personne n'étudiait à l'époque. Comme c'est un état de la matière qui est assez amusant, je me suis lancé dedans. Et il se trouve qu'en même temps que je travaillais sur les gels d'oxyde de vanadium, les verriers travaillaient sur les gels de silice. On s'est rencontré et puis on a travaillé ensemble.

A ce moment-là, du côté américain, il n'y avait pas grand monde. La Materials Society à Boston comptait une cinquantaine de personnes, pas plus. En France, on a créé un groupe sol-gel au CNRS qui regroupait une quinzaine de laboratoires français. C'était dans les années 80-90. C'était vraiment le démarrage : on rassemblait des laboratoires de chimie organique et de chimie minérale. Il y a eu des séminaires, des écoles d'été. Ensuite, avec des collègues allemands, on a fait un groupe européen et ensuite ça s'est diversifié.

Le domaine s'est constitué d'abord avec les verriers (les laboratoires de recherche sur le verre qui étudiaient les gels de silice). Ensuite se sont joints les céramistes dans le domaine de Materials Science qui ont beaucoup exploité cela pour fabriquer des céramiques. Et maintenant la voie la plus prometteuse ce sont les hybrides. Par la chimie, à température ambiante, on peut mélanger de l'organique et du minéral, en gros tous les intermédiaires entre du plastique, du plexiglass et de la silice, du verre. Et parmi ces matériaux hybrides, il y a un petit volet qui ne s'est pas encore développé : celui où au lieu de l'organique on a affaire à du biologique. Il s'agit d'insérer des enzymes, des cellules, des bactéries, des choses comme ça et de les faire travailler dans du verre.

BBV : Quelles peuvent être les applications de ces hybrides ?

JL : Pour ces matériaux hybrides ce sont les applications optiques qui sont actuellement en plein essor. On met des colorants organiques dans du verre. En fait, il y a des applications réelles, commerciales : typiquement des films minces sur du verre . Il y a pas mal d'industries qui ont lancé des départements sols-gels, par exemple le CEA.

L'oxyde de vanadium a des applications multiples :

- semi-conducteur on l'utilise en film mince pour les dorsales antistatiques. C'est facile on l'étale au pinceau. Le premier brevet pour l'application en couche mince est un brevet allemand (à Iena) de 1939. Mais le procédé ne fut commercialisé qu'en 1959
- c'est l'un des rares matériaux minéraux qui présente un comportement cristal liquide
- on l'utilise comme matériau d'électrode dans les batteries au lithium. Il a un fort potentiel, 3 volts et se laisse mettre en couche mince. Il est donc envisagé pour les portables ;
- au Japon et aux USA on l'utilise aussi comme solvant pour des liants.
- Une application plus classique mais pas encore commerciale concerne l'affichage électrochrome comme l'oxyde de tungstène.

BBV : Vous avez toujours travaillé en étroite collaboration avec l'industrie. Quelles sont les modalités de votre collaboration ?

JL : C'est essentiellement du financement de thèses et de post-doc. Actuellement les brevets sont pris par des industriels avec les noms des auteurs. Les brevets, les licences d'exploitation ce n'est pas nous. Nous n'en retirons aucun bénéfice financier. Nous les bénéfices que l'on a c'est

- que l'industrie finance des post-docs,
- qu'ils embauchent pas mal de gens qui sortent du labo. C'est quand même important pour un laboratoire de recherche et de formation.

BBV : Dans quelle mesure ces liens avec l'industrie ont-ils orienté le cours de vos recherches ?

JL : Au début, on l'a vu, c'est un intérêt industriel qui m'a aiguillé vers les gels. Mais après je ne pense pas qu'il y ait eu de virages. Les enjeux des gels sont très importants pour l'industrie et on était un des rares labos à faire de la recherche fondamentale en ce domaine. En fait c'est toute la chimie des solutions aqueuses. Toute l'industrie des céramiques, des catalyseurs des pigments utilisent déjà ces procédés mais n'en ont pas la science. On a plus apporté un savoir faire, une compréhension, une matière grise que des solutions à des problèmes directs.

BBV : Quelles sont les opérations que vous faites avec ces gels ? Quel genre de techniques utilisez-vous ?

JL : La caractérisation des gels n'est pas facile. Ce sont des systèmes qui ne sont pas cristallins.. La technique la plus importante c'est la RMN et puis l'absorption X les XAS.

La première étape c'est l'élaboration. Faire un gel c'est comme une mayonnaise, il faut le coup de main et puis il faut comprendre le pourquoi et le comment. On a un gel dans un flacon. C'est joli mais pour savoir ce qu'il y a dedans la deuxième étape c'est la caractérisation et puis après il faut voir s'il n'a pas de propriétés intéressantes. Les propriétés essentielles qu'on étudie au laboratoire sont des propriétés optiques et électriques.

BBV : Allez-vous jusqu'à l'étape de la fabrication de prototypes ?

JL : Prototype de laboratoire, non sophistiqué, oui. Mais pas les prototypes industriels. On n'est pas du tout équipé pour ça. De plus, je ne connais pas les besoins économiques. On a déposé une quinzaine de brevets sur 5 années. Mais toujours pris par les industriels. La seule fois où j'ai pris un brevet d'Etat par l'ANVAR cela a bloqué une collaboration avec Saint-Gobain.

C'est peut-être une politique personnelle mais j'ai choisi de faire de la recherche fondamentale et l'institution nous juge sur cette science.

Notre point fort c'est plutôt la matière grise. C'est de la chimie fondamentale. La chimie la plus répandue dans le monde est la chimie des solutions aqueuses. Du point de vue industriel c'est évidemment la moins chère, la plus simple. Et curieusement les connaissances théoriques là dessus sont beaucoup moins développées qu'en chimie organique.

BBV : Quels sont les problèmes théoriques soulevés par les gels ?

JL : Le problème essentiel est de savoir quelles sont les espèces que l'on a dans la solution. En général on n'a pas une espèce mais un mélange, très fugace donc des dynamiques, des cinétiques très rapides. Il n'est donc pas évident de savoir qui est important dans un bécher. Une fois que l'on a compris les mécanismes on peut maîtriser le système et fabriquer ce que l'on veut.

BBV : Comment nommer cette chimie ?

JL : "Chimie des hautes températures", c'était exclu vu qu'on travaille à température ambiante. "Chimie du solide" ne convenait plus, vu que les gels c'est de la matière molle.Chimie de la matière condensée c'était le pendant de la physique de la matière condensée pratqiuée au laboratoire de De Gennes.

BBV : Dans quelles circonstances avez vous lancé l'expression « chimie douce » ?

JL : Chimie douce est une expression que j'ai avancée du temps où j'étais journaliste scientifique. C'est une époque où j'écrivais un article dans Le Monde tous les mois. C'est le titre d'un article publié le 26 octobre 1977 dans Le Monde. C'était au moment du choc pétrolier, des problèmes d'énergie. L'idée était la suivante : ce que l'homme ave l'industrie fabrique à des hautes températures, la matière vivante le fabrique à température ambiante. Il y avait donc peut-être quelque chose à apprendre de ce côté là.

BBV : C'était donc une inspiration biomimétique ?

JL : Tout à fait. Absolument.

BBV : Quel est le devenir de cette expression chimie douce ?

JL : L'expression a été reprise facilement, indépendamment de moi. Dans les milieux anglo-saxons on parle de « chimie douce » en français et non de soft chemistry. De toute façon aux USA tous ces secteurs de chimie du solide, de la matière condensée etc sont couverts par l'ombrelle Materials Science.

Sol-gel n'est que l'un des aspects de la chimie douce. Elle comprend aussi la biominéralisation, les composés d'intercalation. Rouxel avait coutume de distinguer deux classes de composés en chimie du solide :

- à précurseur moléculaire (par précipitation)
- à précurseur liquide comme les argiles ce sont les composés d'intercalation.

La chimie douce suppose toujours une phase liquide : d'où la mobilité des ions.

BBV : Dans quelle communauté êtes-vous inséré. Dans quel journaux publiez-vous ?

JL : Dans des revues de physique, le Journal of Solid State Chemistry ; Chemistry of Materials. Il existe bien un Journal of Sol-Gel Science and Technology mais il n'a pas acquis le prestige des journaux de chimie des matériaux.

Tous les deux ans, nous avons un congrès de la communauté sol-gel. Le premier a eu lieu en 1981 en Italie. 300 ou 400 personnes se réunissent. Si l'on compte que chaque laboratoire envoie environ deux personnes on peut évaluer la communauté à 3 ou 4000 chercheurs.
Les pays forts en ce domaine sont les USA (verriers et céramistes), la France et le Japon. Puis l'Allemagne, la grande Bretagne et l'Italie.

BBV : Avez vous des contacts avec la chimie des colloïdes ?

JL : Peu de contacts. La chimie des colloïdes est plus orientée vers la recherche fondamentale sur les problèmes de surface. Sol-gel, c'est très industriel. Notre chance c'est d'intéresser l'industrie tout en faisant des recherches pas trop appliquées.

BBV : Quels sont les effectifs globaux de votre labo ?

JL : Le laboratoire de chimie de la matière condensée appartient à une UMR CNRS intitulée matériaux inorganiques. Elle comprend 100 personnes en trois unités rassemblées sur la montagne Sainte-Geneviève. L'équipe de Chimie de Paris avec Noël Boffier qui fait des batteries ; l'équipe de l'ESPCI avec Philippe Bosch, céramiste ; et notre groupe sol-gel ou chimie de la matière condensée. L'intérêt de cette union c'est 1) qu'on développe une politique commune et ainsi on évite la concurrence ; 2) on a une bonne implantation pour le recrutement des étudiants. J'enseigne à l'ENS et Clément Sanchez à l'X ce qui permet de recruter. Sol-gel n'est pas encore un sujet académique et les jeunes ont tendance à aller vers ce qu'ils ont appris à l'école. Nénamoins les sols-gels attirent les jeunes. Ce qui dans ce temps de pénurie est un gros avantage. On a 15 thésards en moyenne. C'est un labo qui est jeune la moyenne d'âge est inférieure à 40 ans.

BBV : Quelle est la part de l'industrie dans le financement de votre laboratoire ?

JL : 1/3 vient de l'Etat et 2/3 de l'industrie mais ce ratio n'inclut pas les salaires de chercheurs qui viennent de l'Etat. On a aussi beaucoup de contrats européens. La gestion est assurée au niveau central par Jussieu.

BBV : Vous sentez vous appartenir à une communauté de chimistes ou de materials science ?

JL : Non on est clairement chimiste. En France il n'y a pas de Materials Science

BBV : Comment expliquez vous l'échec des tentatives françaises pour constituer quelque chose comme un secteur science des matériaux ?

JL : Il y a eu des efforts faits par le CNRS quand il était question de faire des commissions regroupant physiciens et chimistes. J'étais à l'époque chargé de mission pour chimie et j'ai une des réunions avec mes homologues pour la physique. Mais ça n'a jamais marché. Le public n'a pas suivi. Je pense qu'il y a eu de très bonnes collaborations entre la physique et la chimie. Le CNRS a fait plusieurs tentatives.C'est l'université qui a fait blocage. Blocage dans les structures plus que dans les mentalités. Dans les structures universitaires on est dans des départements différents. La carrière d'un physicien ne dépend pas de celle d'un chimiste.

Ce qui ne veut pas dire qu'ils ne travaillent pas ensemble. Il y a beaucoup de collaborations Par exemple ce que j'ai fait sur les cristaux liquides c'est avec des physiciens d'Orsay. Pas mal de choses en électrochimie, sur les batteries aussi avec des labos de physique mais on vit dans des commissions séparées, au CNRS et à l'Université. Donc ce sont des milieux qui ne sont pas amenés à vivre ensemble. On ne trouve rien comme ces unités aux Etats Unis qui regroupent physique, chimie et mécanique.

Par contre ce qu'on a fait avec les physiciens ce sont des filières d'enseignement, des filières matériaux. Curieusement elles ne se trouvent pas tellement dans les grandes écoles. Mais dans les universités à Montpellier, Bordeaux, Nantes. La demande est profilée en liaison avec la demande industrielle. On recrute à Bac+2 et on les porte à Bac+5. Il y a des industriels parmi les enseignants et des stages en entreprise. Il y a aussi quelques instituts matériaux : à Nantes, Strasbourg, où il y a à la fois des physiciens et des chimistes.

BBV : Quel est le contenu de l'enseignement de matériaux ?

JL : Il est orienté sur trois dominantes. Les polymères, les métaux et les céramiques.

Mais surtout il existait une forte communauté chimie du solide qui occupait déjà la place. Historiquement elle est née avec Hagenmuller et Collongues. C'est là que la chimie minérale est devenue chimie du solide. Les deux familles ennemies (les écoles de Chaudron et de Chrétien) se sont réconciliées par l'intermédiaire de leurs élèves : Hagenmuller et Collongues. Deux personnes fondamentales pour le développement scientifique et pour le fait qu'elles se soient entendues ensemble. Ils ne se sont pas tirés dans les pattes. Ils se sont épaulés. Ils ont été capables de faire une politique scientifique commune. Ce sont deux personnalités très différentes, deux styles différents avec des thèmes de recherche différents. Je crois que c'est là que la communauté s'est soudée avec ces deux rameaux qui se sont bien entendu. et les élèves des uns et des autres ont continué.

Fin de l'enregistrement

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Pour citer l'entretien :

« Entretien avec Jacques Livage », par Bernadette Bensaude-Vincent, 12 décembre 2000 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article122.

—

Entretien avec Jacques Livage, par Bernadette Bensaude-Vincent, 4 janvier 2001

Lieu : Laboratoire de chimie de la matière condensée, Tour 54 (5e étage), Université de Jussieu, Paris, France

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.