Study of Thermal and Electro-Optical Properties of PDLC Doped with ZnO Nanoparticles.

Polymer Dispersed Liquid Crystals (PDLC’s) is a class of material that consist of liquid crystal droplets, dispersed in polymer matrix. PDLC’s operate on the principle of electrically controlled light scattering. This kind of display are very popular as separate polarizer is not needed in the system and are widely used in the application of projection, flexible display, switchable window. They are also promising candidates in the field of nano, bio and micro-technology (photonic devices, holography, microelectronics, actuators, sensors, memory devices) owing to the properties like tunability, bio- degradability, reversibility and flexibility. In the present paper doped and undoped samples of PDLC are studied for Phase Transition Temperature(PTT) using Differential Thermal Analysis(DTA) and Optical Polarizing Microscopy(OPM). The electro optic study of theses samples was carried out for different voltages and % by wt. concentration of ZnO nanoparticles (NPs) to investigate the dependence of concentration and dispersion of nanoparticles in PDLC matrix. It is observed that the clearing point temperature is lowered for doped sample and with better transmission in ON state. Contrast ratio for doped samples are found to be lowered compare to undoped PDLC sample.