Investigation of thermodynamic properties of 4-decyloxybiphenyl 4'-carboxylic acid liquid crystal and preperation of polymer dispersed liquid crystal composite

In this study, firstly, retention behavior of solvents such as n-butyl acetate (nBA), isobutyl acetate (iBA) and tert-butyl acetate (tBA), on the liquid crystalline material 4-Decyloxybiphenyl-4'-carboxylic acid (DSKA) was studied between 60°C and 270°C by inverse gas chromatography technique. Retention diagrams were obtained for the studied liquid crystal-solvent systems. Later on, the interactions of liquid crystal with n-octane (O), n-nonane (N), n-decane (D), tridecane (TD), dodecane (DD), undecane (UD), n-butyl acetate (nBA), isobutyl acetate (iBA), n-propyl benzene (nPB), isopropyl benzene (iPB), ethyl benzene (EB), chloro benzene (KB) and toluene (T) between 245°C and 270°C were examined. Liquid crystal-solvent interaction parameters for Flory-Huggins theory , and equation of state theory , effective exchange energy parameters, , the partial molar heat of mixing at infinite dilution of the solvent , molar heat of vaporization of solvent , the partial molar heat of sorption of the solvent were obtained. Secondly, polymer dispersed liquid crystal (PDLC) composite film in composition 20/80 poly(methyl methacrylate)/DSKA liquid crystal by weight was synthesized by solvent-induced phase seperation method using DSKA liquid crystal and poly(methyl methacrylate) (PMMA). The mesomorphic behaviour of DSKA liquid crystal and PDLC composite has been investigated by differential scanning calorimetry (DSC) and optical polarizing microscopy (PM).