Poling of liquid crystals in thin filmsP.C. Schuddeboom, R. Meister, E. Cecchetto and B. Jérôme
Department of Chemical Engineering, University of Amsterdam Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands email@example.com
(Received 13 December 2002 and Received in final form 31 March 2003 / Published online: 21 May 2003)
We examine the effect of a strong DC electric field on the molecular orientational order and the nonlinear optical response of liquid crystals in thin films. We compare the results of second-harmonic generation measurements with the predictions of two models, one assuming that the dipoles carried by the molecules have no interactions (the isotropic model), and the other assuming that the dipoles evolve in a Maier-Saupe orienting field responsible for the liquid-crystalline order (the Maier-Saupe model). In both cases, we take into account the effect of surfaces and confinement on the behavior of the molecules. We find that the molecular dipoles behave as predicted by the isotropic model, but that their reorientation is correlated in such a way that the apparent dipole moment of the reorienting units is one order of magnitude larger than the molecular dipole moment.
61.30.Gd - Orientational order of liquid crystals; electric and magnetic field effects on order.
61.30.Hn - Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions .
42.70.Df - Liquid crystals.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003