Thermodynamic and surface characterisation of (S)-5-dodecycloxy-2-[[[4-(2-methylbutoxy)phenyl]imino]metheyl]phenol thermotropic liquid crystal by inverse gas chromatography

Abstract

The inverse gas chromatography method was used to obtain thermodynamic and surface properties of the calamitic thermotropic liquid crystalline material, (S)-5-dodecyloxy-2-[[[4-(2-methylbutoxy)phenyl]imino]methyl]phenol, which is a Schiff base. The retention diagrams of the infinitely diluted solutions of acetate and alcohol isomers of (S)-5-dodecyloxy-2-[[[4-(2-methylbutoxy) phenyl]imino]methyl]phenol were plotted between 313 and 383 K using the inverse gas chromatography method. The isomer seperation of (S)-5-dodecyloxy-2-[[[4-(2-methylbutoxy) phenyl]imino]methyl]phenol isomers as chromatographic probes was represented by retention diagrams. The thermodynamic interaction parameters such as the Flory-Huggins liquid crystal-solvent parameter and the hard-core liquid crystal-solvent parameter, the weight fraction activity coefficient and the exchange parameters such as the effective energy, enthalpy and entropy were determined for the studied solvents at infinite dilution. Then the partial molar heat of sorption, the partial molar heat of mixing at infinite dilution and as well as the molar heat of vaporisation of the studied solvents were determined in the isotropic phase of (S)-5-dodecyloxy-2-[[[4-(2-methylbutoxy) phenyl]imino]methyl]phenol. To characterise the surface properties of (S)-5-dodecyloxy-2-[[[4-(2-methylbutoxy) phenyl]imino]methyl]phenol, retention diagrams of several non-polar and polar solvents with (S)-5-dodecyloxy-2-[[[4-(2-methylbutoxy) phenyl]imino]methyl]phenol were measured in the temperature range from 313 to 333 K by inverse gas chromatography. The surface energy, the thermodynamic adsorption parameters and the acid-base constants of (S)-5-dodecyloxy-2-[[[4-(2-methylbutoxy) phenyl]imino]methyl]phenol in the crystalline phase were determined.