Studies on Some Chiral Liquid Crystal Mixtures

Abstract

Chirality has become the most important and complex topic of research in liquid crystals today. The reduced symmetry in these organized phases leads to a variety of novel phase structures, properties, and technological applications. In the present work the concentration of chiral dopant has been varied to improve cell performance and determine the most appropriate electro-optic response in terms of parameters, such as optical transmission, threshold voltage, and response time and decay time as a function of temperature, applied voltage and chiral dopant concentration. The role of chiral dopant on helix dynamics as a function of temperature and electric field has been discussed in detail. We also reported the effects of chiral dopant in room temperature nematic liquid crystal mixture on its thermo-chromic responses in terms of Red, Green, Blue (RGB), hue and intensity of transmitted beam. In the present work three step reactions for synthesis of novel side chain chiral liquid crystal polymers of high molecular weight has been discussed in detail and influence of chiral doping introduced in the liquid crystal polysiloxanes on phase sequence and electro-optic properties studied. The thesis work also deals with the morphological, opto electronic and opto dielectric responses in chiral smectic C liquid crystal mixture, containing low concentration of carbon nanotubes.