We report ellipsometric measurements on freely suspended films of chiral liquid-crystal compounds near their smectic-A - smectic-C transition. The temperature difference between the surface and the bulk transition is found to vary considerably within a homologous series. In two compounds possessing a fluorinated alkyl chain an unexpected sign inversion of the spontaneous polarization in the ferroelectric smectic-C phase is observed which occurs only in thin but not in thick films.
|Original language||English (US)|
|Number of pages||9|
|State||Published - 1998|
|Event||Proceedings of the 1997 6th International Conference on Ferroelectrics Liquid Crystals. Part 1 (of 3) - Brest, Fr|
Duration: Jul 20 1997 → Jul 24 1997
Bibliographical noteFunding Information:
This work was supported in part by the Deutsche Forschungsgemein-schaft (grant no. Ba1048/5-l), the Fonds der Chemischen Industrie, and National Science Foundation, Solid State Chemistry Program, (grant no. DMR-93-00781). Ch. B. is grateful to the Deutsche Forschungsgemein-schaft for a Heisenberg-Fellowship. We would like to thank Dr. G. Janulis (3M Corporation, St. Paul, MN) for providing the fluorinated 'compounds.