<title>Influence of light-induced molecular conformational transformation and anchoring energy on the cholesteric liquid-crystal pitch and dielectric properties</title>

Abstract

A cholesteric liquid crystal (CLC) is considered in a cell with planar boundary conditions, in which long-lived metastable states of molecules with the conformation different from that of initial molecules are formed under the action of light. The phenomenon of molecular phototransformation was suggested to be used for varying the cholesteric twisting ability and, thus for controlling the CLC pitch. The dependence of the pitch on both the molecular twisting ability and the anchoring energy of director with oriented cell planes was investigated. The expression is derived for the anchoring energy which makes it possible to determine its value through the experimentally measured data. It is shown that with discontinuous change of a pitch there may occur a jump of mean values of components of the CLC dielectric susceptibility tensor. The preliminary experiment is discussed.