Applicability of TiO2 nanoparticle towards suppression of screening effect in nematic liquid crystal

We report the preliminary results observed for TiO2 nanoparticles dispersed nematic liquid crystal. We observed that dispersion of TiO2 nanoparticles (NPs) in nematic liquid crystal (NLC) has suppressed the undesired ionic effect. However unpurified nanoparticles lead to increase in the ionic conductivity, due to insertion of some more impurities. The pristine and dispersed NPs in NLC have been examined by means of optical texture, optical transmittance and dielectric spectroscopy. The diminution of ionic effects has been attributed to the strong adsorption of ionic impurities on the surface of TiO2 nanoparticles. Almost all of the ions have been adsorbed on the surface of NPs at a loading of 1 wt% in NLC. Also we didn't find any considerable change in the transition temperature of NLC, except for 2 wt.% loading. The optical transmittance curve reveals that relaxation processes are faster than the host materials, after the field is turned off. The faster relaxation in dispersed system is ascribed to the decrease in the rotational viscosity and suppressed screening effect The present study is helpful in understanding the phenomenon of suppressing the screening effect, caused by the ionic movements under applied field of LC based devices, without affecting the transition temperature of liquid crystalline material. (C) 2015 Elsevier B.V. All rights reserved.