Electric-Field-Induced Texture Transformation and Pitch Contraction in a Cholesteric Liquid Crystal

Abstract

D.C. electric-field-induced pitch contraction and a simultaneous transition from the cholesteric plane texture to the focal conic texture were studied microsopically in a mixture of 20% cholesteryl chloride and 80% cholesteryl oleyl carbonate. The texture change is preceded by the formation of a periodic pattern in the plane texture. The decrease in helix pitch p is very small for applied fields less than 25 kV/cm: above this threshold field the decrease if greater: dp/dv = 0.33nm/V. In the latter region the increase in reciprocal pitch length is proportional to the applied field, in aggrement with Meyer's theory. However, the experimental slope is much less than predicted.