ELECTRIC FIELD EFFECTS ON DIELECTRIC PROPERTIES AND MOLECULAR ARRANGEMENTS OF CHOLESTERIC LIQUID CRYSTALS

Measurements of dielectric constants of a cholesteryl chloride-cholesteryl myristate mixture having a strongly temperature-dependent helical pitch have been performed in the presence and absence of an applied dc electric field. An analysis of the molecular arrangement in samples oriented by wall effects is presented, as well as the perturbations in this arrangement which occur both thermally and by the application of an electric field. Elastic moduli of bending and torsional strain are estimated from the threshold electric fields observed to (a) induce helical perturbation and (b) destroy the helical structure in the transition to a nematic phase.