Effect of graphene oxide dispersion in antiferroelectric liquid crystal mixture in the verge of SmC* to SmCA* phase transition

Abstract

The continuous growing demand for nanoscience applications and the improvement in the performance of liquid crystal based devices has been extensively required by the technological world. Recent progress in the field of liquid crystals has found its practical implementation in various display and non display devices which experiences obstacle due to impurity effects that reduces its performance. The dispersion of nanoparticles in liquid crystal medium helps in the reduction of impurity ions and thus improving the performance of liquid crystal based devices. The present work is based on the collective dielectric relaxation processes that have been observed in antiferroelectric liquid crystal (AFLC) mixture W1000 dispersed with 0.1% wt/wt and 0.3% wt/wt concentrations of graphene oxide. Graphene oxide itself favors vertical alignment and the coupling of AFLC W1000 mixture with graphene oxide affects its molecular ordering. This has been confirmed from the polarizing optical micrographs. The dielectric relaxation modes have been observed with and without the application of bias voltage in SmC* to SmCA* phase transition during cooling cycle. The appearance and disappearance of PL, PH and X modes have been observed and are explained on the basis of molecular interactions. Graphene oxide dispersed system favors homeotropic alignment (dark state) and the application of bias field will convert it into homogenous alignment (bright state). Graphene oxide dispersion find prospective applications in good contrast display devices, supercapacitors, electronic gadgets, rechargeable batteries. Electro optical results unveil the faster response time, decreased rotational viscosity and spontaneous polarization with no change in tilt angle for the dispersed system. These observations can be exploited in photonic switches with sub millisecond response time which are required for fabricating faster liquid crystal devices.