Fluorination in Nematic Systems

Abstract

The effect of fluorine substitution into a mesogenic system depends critically on the manner in which it is introduced. The relative stabilities of smectic and nematic phases may be inverted by altering the site of substitution, and lateral fluorination is particularly interesting for the strong suppression of smectic phase stability which can result. This effect has been applied to hydrocarbon mesogens to obtain new series of wide range, room temperature nematics of low viscosity and moderately high birefringence. These properties are readily conferred on mixtures, and the technical utility of fluorinated LC's is illustrated by reference to wide nematic range, fast switching mixtures having high birefringence, and suitable for static or multiplex drive.