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-4′-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-4′-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-4′-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 μs. This liquid crystal physical gel has potential for use in light scattering electro-optical displays