JCIS 483-2016-41

Liquid crystal physical gel formed by cholesteryl stearate for light
scattering display material

A liquid crystal physical gel was prepared by the self-assembly of cholesteryl stearate in a nematic liquid
crystal, 4-cyano-40-pentylbiphenyl. The electro-optical properties were tuned by varying the gelator concentration
and the gelation conditions. Polarized optical microscopy revealed that cholesteric cholesteryl
stearate induced chiral nematic phase in 4-cyano-40-pentylbiphenyl during the gelation process. As a
result, a plate-like gel structure consisting of spherical micropores was formed, as observed by scanning
electron microscopy. Electron spin resonance spectroscopy showed that the liquid crystal director orientations
in these macrophase-separated structures were massively randomised. For these reasons, the liquid
crystal physical gel generated a strong light scattering effect. For 48.0 wt% cholesteryl stearate gelled
4-cyano-40-pentylbiphenyl, the turbid appearance could be switched to a transparent state using a 5.0 V
alternating current. The response time was about 3.7 ls. This liquid crystal physical gel has potential for
use in light scattering electro-optical displays.