Thermodynamic and surface characterisation of 4-[4-((S)-citronellyloxy) benzoyloxy] benzoic acid thermotropic liquid crystal

Abstract

The inverse gas chromatography (IGC) method was used to obtain thermodynamic and surface properties of the thermotropic liquid crystalline material, 4-[4-((S)-citronellyloxy)benzoyloxy] benzoic acid (CBB). Liquid crystal (LC) selectivity was investigated using the alcohol and acetate isomers by the IGC method at temperatures between 338.2 K and 463.2 K. The retention diagrams of n-decane, undecane, dodecane, tridecane, n-butyl acetate, iso-butyl acetate, ethylbenzene and chlorobenzene on CBB were plotted in the temperature range between 468.2 K and 493.2 K. The specific retention volume, V-g(0), Flory-Huggins interaction parameter, x12, equation-of- state interaction parameter, x*12, the partial molar heat of sorption, Delta H-1(s), the partial molar heat of mixing,. similar to H11, the molar heat of vaporization,. Delta HV and the weight fraction activity coefficient, O11, were determined. The dispersive component of the surface free energy, gamma(D)(S), of the studied adsorbent surface was estimated in the infinite dilution region. The specific free energy of adsorption, Delta G(A)(S), the enthalpy of adsorption, Delta H-A(S) and the entropy of adsorption, Delta S-A(S) of solvents on LC were determined. The values of.HS A were correlated with the donor and the acceptor numbers of the probes to quantify the acidic K-A and the basic K-D parameters of the LC surface. The values obtained for K-A and K-D parameters indicated an acidic character for the surface of CBB.