Control of Helical Structure of (Liquid Crystal/Polymer Liquid Crystal) Composites by Photoisomerization of Chiral Azobenzene Molecules

Abstract

A compensated nematic liquid crystal (LCs) were prepared by mixing of a chiral azobenzene and a nonphotochromic chiral compound giving mutual opposite helical sense in a host nemati LC. Reversible optical switching between transparent and opaque was achieved by ultraviolet and visible light irradiation. The photochemically switched opaque state was not stable even in the dark. Stability of the opaque state was improved by adding polymer LC in the low molecular weight compensated nematic LC.