Influence of dielectric relaxation times of fluid mixtures on solid/liquid interfacial tension

The study presents the results of spreading behaviour of pure fluids like glycerol (Gly), ethylene glycol (Eg), diethyleneglycol (Dieg), 2-methoxy ethanol (2Me) and their mixed systems with water on solids like glass, mica and Teflon under gravitational and interfacial forces. Monte Carlo simulation using the Flory–Huggins theory has been used to study the extent of mixing of the solvents as well as the free energy of solvation. Dielectric relaxation times of these mixtures have been related to the solid/liquid interfacial tension. The dielectric relaxation times play an important role for viscous droplets, and have a significant effect on the solid/liquid interfacial tension at low contact angles. While liquid drops on Teflon and mica show a direct correlation between solid/liquid interfacial tension and dielectric constants, on glass there seems to exist an inverse relationship suggesting that the induced charges on glass surface may play an important role in the interfacial process. Shorter relaxation times with positive solid/liquid interfacial tension demonstrated lower interaction of fluids with the solids while for polar solvents on polar substrates dielectric relaxation times were longer suggesting better interaction.