Investigation of Parameters of Liquid Crystal Composite System

Using a number of techniques, investigations have been carried out for forty-eight different systems of sample combinations according to varying components and different concentrations of pure Liquid crystals(LCs) Cholesteryl Pelargonate (CP) as well as Composite systems formed with polymer of metha methyl acrylate (PMMA-a clear plastic) in different proportions with azobenzene dye (Orange). The Phase Transition Temperatures (PTTs) were found using the Fabry-Perot Scattering Studies (FPSS). The textures and the PTTs of pure CP have been studied using the supplementary techniques of Differential Thermal Analysis (DTA) and Polarising Microscopy Studies (PMS). The absorption of the sample in the visible range was found using Ultra-Violet visible spectroscopy (UV-VIS). The infrared absorption was also studied using Fourier Transform Infrared (FTIR) spectroscopy. The results of the above investigations are being presented here. Addition of azobenzene dye to pure CP decreased its clearing temperature from 88C to 62.8C. A comparative study between the systems, with and without azodye, showed that the addition of azobenzene dye brought about a change in the PMS textures indicating a change in the birefringence properties. Further, the clearing temperature also varied with different concentrations of PMMA in the mixture of CP + azodye; the clearing temperature was maximum (77.5C) for the sample which contains 80%CP+20%PMMA+1% Azodye). Results of the UV/VIS analysis, FTIR analysis are also presented and discussed in this paper.