Effect of temperature dependence of deformation polarizability and ionization energy of solvents on surface properties of solid materials

Abstract

In recent studies, an original approach based on the London interaction equation has been proposed for the determination of the dispersive and polar surface properties of solid materials. The reported results revealed significant deviations in surface parameters compared with those obtained using classical methods. However, in these earlier works, the ionization energy and the deformation polarizability of solids and probe molecules were assumed to be temperature-independent. In the present work, the effect of temperature on these two fundamental molecular parameters is investigated, and the influence of their temperature dependence on the surface properties associated with the adsorption of organic solvents on oxide materials such as alumina, titania, and magnesium oxide is examined. Inverse gas chromatography (IGC) at infinite dilution is employed to determine the net retention volumes of probe molecules, enabling the calculation of the free energy of adsorption, as well as its dispersive and polar components, the Lewis acid–base parameters, and the corresponding surface energies. The results demonstrate that thermal variations in ionization energy and deformation polarizability—although relatively small—have a pronounced impact on surface thermodynamic parameters. In particular, changes of up to 100% are observed in the dispersive and polar components of the adsorption free energy for several probe molecules, while variations in the Lewis acid–base constants of solid surfaces reach up to 200% in the case of magnesium oxide. These findings clearly highlight the high sensitivity of surface properties to temperature-dependent molecular parameters and emphasize the necessity of explicitly accounting for thermal effects in the analysis of surface–molecule interactions.