Hansen Solubility Parameters for Directly Dealing with Surface and Interfacial Phenomena

To integrate surface and interfacial properties and phenomena into the Hansen solubility parameter (HSP) framework, we propose an equation for estimating both surface tension/energy for liquids and solids as well as interfacial tension/energy. The contact angles of probe liquids on various polymers estimated using the proposed equation based on bulk HSPs (derived from bulk properties such as solubility or swelling, and not on surface properties) are compared with those measured using the sessile drop method. It is found that their correlations are sufficient for predicting wettability in practical use. All the respective tension and energy correlations are reasonably good, confirming the predictive power of the proposed equation for all values of liquid surface tension, solid surface energy, and interfacial tension. The unification of surface and interfacial properties and phenomena with HSPs (derived from bulk properties) enables us to estimate the surface properties from bulk properties and vice versa. The huge database of HSPs is now applicable to not only bulk phenomena but also surface and interfacial phenomena. Furthermore, complex processes or systems composed of multiple constituents and phases can be understood and designed using the modified HSP framework.