Thermodynamic properties of liquid crystals and synthesis and characterization of polymer dispersed liquid crystal composites

In thesis study, firstly the phase transition temperatures of 5-((S)-3,7-dimethyloctyloxy)-2-[[[4-(dodecyloxy)phenyl]imino]-methyl]phenol and 5-((S)-3,7-dimethyloctyloxy)-2-[[[4-(octyloxy)phenyl]imino]methyl]phenol liquid crystals were investigated by optical polarising microscopy (PM) and differential scanning calorimetry (DSC). After that, the retention diagrams were plotted for liquid crystal-solvent systems by inverse gas chromatography method. Thermodynamic equation temperatures were determined from these retention diagrams and infinite dilution activity coefficients, Flory–Huggins and equation of state interaction parameters, effective exchange energy parameters were calculated in this temperature range. Secondly, isomer selectivity, thermodynamic parameters of adsorption (free energy, enthalpy and entrophy), dispersive components of the surface energies, the acid and base constants were calculated. Lastly, polymer dispersed liquid cyrstal (PDLC) composite films were prepared by solvent phase-seperation method (SIPS) using poly(methyl methacrylate) (PMMA) and new chiral calamitic liquid crystal compound. The morphological and thermal properties of prepared composites were determined by Scanning Electron Microscopy (SEM) and (DSC), respectively. Keywords: Liquid crystal, inverse gas chromatography, polymer dispersed liquid crystal composite