Twisted Grain Boundary Phase in Binary Mixture of Liquid Crystals

Abstract

In the present work, our investigation is to study the optical and thermal properties of the binary mixture of cholesteric and nematic compounds, namely, cholesteryl chloride and 4,4′-hexyloxy azoxy benzene, which exhibits a very interesting liquid crystalline twisted grain boundary (TGB) phase and induced smectic phases like SmA, SmC*, SmE, and SmB phases. The chiral liquid crystalline TGB phases have been observed at different concentrations and at different temperatures. The mixture with concentration from 26% to 37% of shows I-Ch-TGB-SmA-SmC*-SmE-SmB phases sequentially when the specimen cooled from isotropic phase. The existence of TGB phase is confirmed by DSC and optical microscopic studies. The temperature variation of optical anisotropy is also discussed. X-ray studies have been carried out to understand the intermolecular interactions in the mixture. With the help of phase diagram, the phase behavior has also been discussed.