Acid base contributions to interfacial free energy: self-consistency considerations

The evaluation of interfacial free energies is a subject of much discussion . Of recent times, the role of acid/base interactions has been much debated and a mathematical model devised by van Oss et al. is now commonly used. I n this work, we study several polymers using recognised probe liquids and, exploiting an extended matrix analysis, obtain values of solid surface char acteristics in agreement with literature values. However, by 'inverting' th e method, and using accepted solid surface characteristics to 'rederive' su rface free energy parameters for probe liquids, inconsistencies become appa rent. Despite the conceptual interest of acid/base interactions, clearly th e mathematical formulation of van Oss et al. is incomplete and further deve lopment is required. (C) Academie des sciences/Elsevier, Paris.