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Abstract
Before 1910, the study of liquid crystals was dominated by Lehmann and the German school of chemists. The point of gravity then moved to France with Friedel as a leading figure. While there are many studies about Lehmann, there are fewer about Friedel. He has written about himself, so to speak, and more people have cited him than read his original papers. In the first part of this historical review, I will, after a close reading of the original papers, trace the development on French soil between 1910 and 1922.
After 1922, the progress stopped in France, but a renewal of interest in liquid crystals came from Germany in the late 1920s and the first international symposium was organised there in 1931, closely followed by one in England 1933. After the Second World War, a new symposium in 1958 revived the field and then came a new outburst of turbulent productivity in the late 1960s. My aim is to focus on some of the most prominent persons and some turning points also in this modern era. But my foremost aim is to illustrate that nothing happened in the straightforward way in which most texts tend to outline the history.
Acknowledgements
When, about 10 years after my PhD (in nuclear science), I decided to switch field completely, after having read some beautiful papers by de Gennes, I was by then fairly old but had the fortune to be accepted by de Gennes to spend one year and a half in the Orsay Group. There I also met two visiting Americans, Irl Smith from MIT and Bob Meyer from Harvard. They were my first teachers. I also owe much to Yves Galerne and Roland Ribotta. I was present when Bob Meyer demonstrated the first liquid crystal with an inherent, spontaneous polarisation, a tilted chiral smectic synthesised expressively on his demand by the Orsay chemists. A little later, I met my main teacher Noel Clark, who was from the same Harvard Group as Bob. Both of them spent periods in my lab in Sweden that were very important for me and for my young group of students. My gratitude goes especially to Noel Clark with whom I now have had a long time of fruitful collaboration.
This research was funded by a grant from the Royal Academy of Arts and Sciences in Göteborg.
Notes
1. 1. A modern reader who often has to wait many months to get a paper refereed might be jealous at the publication policy of 1910. Most of the papers just under discussion appeared with only weekly intervals.
2. 2. Among Weiss’ students were G. Foex and L. Néel. Foex would later (in the beginning with L. Royer) make magnetic measurements on nematics, and he is one of the participants of the Faraday meeting in 1933. Louis Néel (1904–2000) made his PhD in 1932 and was then professor in Strasbourg 1933–1945 when he moved to Grenoble. He got the Nobel prize in 1970 for his work on ferri- and antiferromagnetism.
3. 3. Louis Royer (1895–1980) went on to a distinguished career in crystallography and mineralogy. After his PhD, he went to Montpellier (where Jacques Curie was a professor of mineralogy) as maître de conférences and, in 1930, became professor of mineralogy at the Faculté des sciences in Alger. Royer was the foremost expert in epitaxy, a word that he coined and the laws of which he developed already in 1928. When, after the Algerian war (1954–1962) the previous French colony proclaimed its independence, Royer had to leave Algeria (together with 200,000 other Europeans) and went to Marseille. He finally settled in Nice.
4. 4. No. 25 is an unusual example because it is a lyotropic liquid crystal, showing nematic and smectic phases. It was provided by the Swedish chemist H. Sandqvist in Uppsala.
5. 5. It would be historically very worthwhile to republish a selection of the texture photographs taken by the German scientists from this epoch.
6. 6. I have this information from Frank Giesselmann, Stuttgart. This film has been lost during the war, but in a collaboration between an artist and a scientist at the University of Stuttgart, a similar film was produced this year following Lehmann’s preparation recipes. It is said to be spectacular and will soon be available on internet.
7. 7. No wonder. To tell that something has a structure that is between some other structures is not very descriptive. There are lot of things that could be said to be between something else. In contrast, liquid crystal is, as already Mauguin pointed out, a rather descriptive expression.
8. 8. Friedel does not give any reference, he only mentions Björnståhl by name, but the only work he could possibly refer to is Björnståhl Y. Annalen der Physik. 1918;56:161–207. In this work, Björnståhl (rather vaguely) describes a light scattering effect on raising the field above a certain threshold. Today, we know that this effect is due to field-induced convectional instabilities. Nowhere in this work is there any mentioning that the optic axis would align perpendicular to the field. Yngve Björnståhl (1888–1942) was a student in the Institute of Physical Chemistry headed by The Svedberg in Uppsala (The is an abbreviation for Theodor). The work just referred to was done for his degree of Licenciate. Svedberg (1884–1971), who is best known for his development of the ultracentrifuge, had in 1913 started to investigate the electrical conductivity of liquid crystals in the presence of electric and magnetic fields. He concluded that the conductivity was higher along the electric field than across it and presumed that this was due to an aligning effect by the field. This was the origin of Björnståhl’s work. Björnståhl took his PhD under Svedberg in 1924. A large part of his research was devoted to the study of the Kerr and Cotton-Mouton effects in a diversity of colloids. He was, in addition, all the time an invaluable person as in-charge of the laboratory and making technical improvements to the ultra-centrifuge, but he never got a higher academic position. An unmarried recluse and suffering from poor health, he died by a drowning accident (thought by many to have been suicide).
9. 9. While Friedel was born to great ambitions (and perhaps a tendency to overestimate himself) in a grande famille, both Mauguin and Grandjean were of humble origins: Mauguin’s father was a baker in a little provincial town and Grandjean’s father was a railwayman.
10. 10. It is amusing to note that 10 years later Charles Frank, then on leave from Oxford, would spend some time at the nearby Kaiser Wilhelm Institute for physics and publish his first paper on liquid crystals in the same journal; Frank, F.C., Quasi-crystalline and crystalline liquids, Physik. Zeitschr. 1938;39:530.
11. 11. This technique is called ‘Chatelain rubbing’ by the French. Pierre Chatelain had to reinvent this method by himself in Montpellier during the war; Chatelain P. Sur l’orientation des cristaux liquides par les surfaces frottées; étude experimentale, CR Acad Sci Paris 1941;213:875 and Sur l’orientation des cristaux liquides par les surfaces frottées, Bull Soc Fr Minéral. 1943;66:105; these two Chatelain papers are reproduced in [1].
12. 12. Leonard Ornstein made a PhD in theoretical physics in 1908, but later turned to an experimental physicist. His classic paper with Frits Zernike Accidental deviations of density and opalescence at the critical point of a single substance was published in 1914. It is surprising that with this background, he could be an adherer to the swarm theory rather than the continuum theory. Being Jewish, Ornstein shared the fate of many other Jewish intellectuals. Following the German invasion in Holland, he was dismissed from his university functions at the end of 1940, and according to Oseen, he committed suicide in May 1941. Ornstein could have anticipated his fate from what was happening in Germany at the time. A well-known case is the outstanding mathematician Felix Hausdorff, professor in Bonn (‘Hausdorff measure’, ‘Hausdorff dimension’ and ‘Hausdorff space’). He lost his position already in 1935 and committed suicide together with his wife and sister-law in 1942 before being taken to the concentration camps.
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Sven T. Lagerwall
Sven T. Lagerwall ([email protected]) is emeritus professor of physics at Chalmers University of Technology in Göteborg, Sweden. He got his PhD from the Technical University of Berlin in 1964 and has been on the faculty at Chalmers since 1966. He is a member of the Royal Academy of Sciences as well as the Royal Swedish Academy of Engineering Sciences.