Textures of ethyl-cyanoethyl cellulose mesophase

Abstract

The characteristic textures of the mesophase in ethyl-cyanoethyl cellulose/dichloroacetic acid cholesteric liquid crystalline solutions were studied under different conditions by means of a polarized light microscope with a hot stage. It was found that the mesophase textures were directly related to the concentration and the temperature of the solutions. With increasing concentration, the disk-like texture changed, first, into an oily-streak texture and then into a randomdomain texture. The disk-like and oily-streak mesophase textures also changed gradually with time into the focalconic texture or the pseudoisotropic texture. Changes in the texture with temperature were affected by thermodynamic and kinetic factors. In the equilibrium state, the mesophase aggregates were smaller at higher temperature than at lower temperature, but their birefringence did not decrease with the temperature.