Fast Switching in the Vicinity of Smectic-to-Nematic Phase Transition in High Birefringence Isothiocyanate Mixtures

Abstract

Two series of high birefringence liquid crystal compounds, isothiocyanato phenyl-tolane and terphenyl, and mixtures were prepared and their physical properties evaluated. Depending on the terminal alkyl chain length, different mesomorphic sequences were observed. In the vicinity of nematic-to-smectic transition, the visco-elastic coefficient decreases, instead of increase, as the temperature decreases. We investigated the possibility of extending the observed phenomenon from single compounds to mixtures for practical applications. This behavior is useful for improving the response time of a liquid crystal device, if the operating temperature can be accurately controlled.