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RTD info logoMagazine on European Research N° 41 - May 2004   
 Europeans’ political blues?
 Doubling European research investment
 Showcasing science
 The allergy enigma
 A parliament in search of voters 

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Title  de Gennes – in perpetual motion

A constant difficulty in scientific research is selecting areas that are ripe but not overripe for investigation. Pierre-Gilles de Gennes (72), a Nobel prizewinner in physics and Professor at the Collège de France, now works on memory neurons and certain aspects of cancer. Earlier voyages of scientific discovery took him into the fields of superconductivity, liquid crystals, polymers, and interfacial science.   We met this untypical researcher.

Pierre-Gilles de Gennes: ‘In Latin countries, there is a tendency to believe that theory governs the universe. I totally disagree. Contact with reality is vital. It is only then, after careful reflection, that one tries to explain.’
Pierre-Gilles de Gennes: ‘In Latin countries, there is a tendency to believe that theory governs the universe. I totally disagree. Contact with reality is vital. It is only then, after careful reflection, that one tries to explain.’
Fascinated by how things work, gifted with a rare spirit of synthesis and exhibiting a deep aversion to routine, Pierre-Gilles de Gennes has, from his earliest youth, struck out from the beaten track. Poor health prevented me from attending primary school. My teacher was my mother.   She had a marvellous knowledge of history and literature and taught me English by reading Jerome K. Jerome's Three men in a boat to me. This was probably not a bad initiation, but I lost a lot in terms of social life....

Since then, de Gennes, far from being an introvert following his several years of solo education, has made up for the lost human contact. Teams are a vital part of research for him. These should preferably be multi-disciplinary teams, involved in a collective effort under the baton, not of a “boss” but someone who guides them in what to look for. De Genne's own priority is to bring together experimental and theoretical scientists. In Latin countries, there is a tendency to believe that theory governs the universe. I totally disagree. Contact with reality is vital. It is only then, after careful reflection, that one tries to explain.

De Genne’s office at the Collège de France is a short walk away from the laboratories where physicists, chemists and biologists are hard at work. Pierre-Gilles de Gennes appreciates this house where he began work in 1971 on being offered the chair in condensed matter physics. ‘It is a place where I can put together my courses in complete freedom. It is still very demanding work, though. Every year I have to present a genuinely new subject, not just describing the current state of knowledge, but adding my own contribution.’

And who comes to hear him speak at this prestigious Collège? Henri Bergson the philosopher and André Chastel, the Curator of the Louvre, used to address elegant ladies in our auditorium. Other personalities lectured to audiences who shared their enthusiasm for a particular field of research or their political commitment. Everything depends on the subject. You are never sure whether what you intend to talk about will interest novice or confirmed researchers, or specialists in one field or another.   For example, I once gave a course on nucleation phenomena to an audience, half of which was passionately interested in the upper atmosphere and the other half in metallurgy… This contact with a mixed and changing public is particularly stimulating.

From neutrons to superconductivity
Let us turn the clock back half a century. Pierre-Gilles de Gennes, aged 23, has just completed the Ecole normale supérieure with a teaching degree in physics. He is talent-spotted by a manager from the Atomic Energy Commission (CEA) at Saclay. They sent a limousine to fetch me. There were new buildings, accelerators, atomic piles on every side. I was amazed – active research usually takes place in much less sumptuous surroundings. I signed an engineering contract and got on like a house on fire with the experimental researchers – they were just starting to use neutrons at the time.

Pierre-Gilles de Gennes spent two years at the CEA, working on neutron scattering and magnetism. After gaining a doctorate in science, he left for Berkeley where he worked under Charles Kittel, one of the masters of solid physics. ‘It felt like we were not doing very much. We spent a lot of time at the pool, but in fact we were working very hard.’ Then came the Algerian war and 27 months in the armed forces, part of it undertaking research. (‘I learned to delve into subjects far removed from my initial interests, which I would never have studied otherwise, for example, marine sciences.’)

Back on civvy street, Pierre-Gilles de Gennes’s career moved into higher gear. In the early sixties he found himself lecturing on quantum mechanics at the new Orsay faculty. Very soon he became fascinated by a subject that had just caused an upheaval in the world of physics – superconductivity, a phenomenon identified by the Dutch physicist Kammerlingh Onnes half a century earlier, but still unexplained. We created an experimental group and persuaded another team to put together a theoretical research unit and cooperate with us. We all worked together in a very collegial manner with most of the scientific communications appearing under the common signature of the Orsay Supraconductivity Group. We did not define a thesis subject for each researcher, but our entire pool of experimental researchers worked in a single research area which we then split up, as necessary, into different areas, giving us very valuable flexibility.

Liquid crystals and tangled polymers
This chapter came to an end four years later. New advances – theoretical and applied – in low temperature superconductivity were slowing. De Gennes' Orsay researchers switched direction to liquid crystals. The experimental dynamism resurfaced and seven teams from the faculty (optics, nuclear resonance, defect research, chemistry, X-rays, hydrodynamics and the theoreticians) decided to pool their specific knowledge to form a liquid crystals group. This research contributed several important advances on the road to liquid crystal screens, including those developed a few years later by the Thomson company.   Our big mistake was failing to concern ourselves with the applications. In those days research was well funded and we gave little thought to patenting our findings.

After this, Pierre-Gilles de Gennes went on to work in polymer physics. Taking advantage of synergies between the Collège de France, which he had just entered, and researchers from Saclay and Strasbourg (the Strasacol Group), he set up a team to focus on molten polymers.   ’These polymeric chains look like a mass of spaghetti. We wanted to understand the how these chains become tangled and untangled in a process that I named reptation, from the way snakes interweave. Our work shed new light on the rheological mechanics of polymers, their plasticity and elasticity and their response to constraints, for example, in the weaving of synthetic textiles.’

For de Gennes, the field of ‘plastics’ represents an exemplary mixture of physics and chemistry, two sciences which ‘need to be treated like twin sisters’. His enthusiasm was confirmed when, in 1976 when he was asked to head up an institute combining the two sciences, l'Ecole supérieure de physique et de chimie industrielle (ESPCI) in Paris, which trains research engineers.

The usefulness of Nobel Prizes
The new boss had his own wishlist. For years he fought to modernise the ESPCI and to teach more avant-garde fields. The decisive moment came when he was awarded the Nobel Prize for Physics in 1991 for his research into ‘phenomena of order in simple systems which can be generalised to more complex forms of matter, and in particular for liquid crystals and polymers’.

So the Nobel Prize was important after all?   ‘Of minor importance,’ de Gennes replies, with a dismissive sweep of his hand, jokingly or out of coquetry, while relighting his ever-present cigarillo. What was important was that they finally listened to what I had to say. This has allowed us to introduce a course in biology and, more recently, a masters in bioengineering taught by neurologists, opticians and acoustic scientists. It took two Nobel Prizes, George Charpak's and mine, to get there....

Pierre-Gilles de Gennes has now left the ESPCI – but he has not quit research. As an adviser to the President of the Institut Curie (which runs a hospital and a cancer research institute) he has been working intensively over recent months on memory problems. We know very little about the brain. In fact it's the greatest scientific problem of our time. I became interested in it through my daughter, who is writing a thesis in neurobiology. I get accused of hopping from one subject to another. Other people spend 20 years on the same problem. Both approaches are necessary.

Is there one field in which Pierre-Gilles de Gennes would claim to be an expert? Experts, you know, are often like military people, experts in the past war but not in the next one.