The surface tension of pure liquids - Thermodynamic components and corresponding states

From the temperature dependency of surface and interfacial tensions the surface excess energy and entropy per unit area can be obtained. The excess energy is a liquid-specific property; it varies over about three decades between liquid helium and molten metals. On the other hand, the excess entropy is, within a certain spread, independent of the liquid, provided the temperature is not far from the melting point: it is a generic property. This entropy constancy implies a corresponding state principle. The surface excess energy and the enthalpy of vaporization are correlated, whereas the constancy of the excess entropy is paralleled by the constancy of the entropy of vaporization (Trouton's rule for surfaces and bulk phases). Consequences for model interpretations of surface tensions are discussed. (C) 1999 Elsevier Science B.V. AII rights reserved.