Thermodynamic Modelling of Systems Containing Liquid Crystalline Phenylbenzoates

Abstract
Systems of nematic (smectic-nematic) liquid crystalline p-butyloxyphenyl p'-n-alkyloxybenzoates (n-alkyl = hexyl, heptyl, nonyl, decyl) with solvents of different classes were studied. The systems were investigated by thermal analysis, polarizing microscopy, visual-polythermal analysis and solubility methods. Temperatures of monotectics and solubility curves of liquid crystals in solvents were obtained. Thermodynamic methods based on the Hildebrand and Hansen solubility parameters were used to predict the phase diagram type. A group-contribution scheme was used to calculate solubility parameters of the liquid crystals. A simple scheme of solvent selection for purification of mesogens was proposed.

Keywords: liquid crystals, phenylbenzoates, solubility, solubility parameter, Hansen solubility parameter