RELATIONSHIP BETWEEN VAPOR-PRESSURE AND SURFACE-ENERGY OF LIQUIDS - APPLICATION TO INVERSE GAS-CHROMATOGRAPHY

First, whatever the nature of the interactions which exist between the molecules of a liquid, it is shown that the logarithm of the vapor pressure Po of the liquid is a linear function of the product of its surface energy γL and the surface area a of one molecule. Second, for nonpolar liquids only, the logarithm of Po is also linearly related to the square root of γL multiplied by a. This latter relationship can be directly applied to the determination of the dispersive component of the surface energy γSD of solids by means of inverse gas chromatography at infinite dilution, relating the free energy of adsorption of nonpolar probes on the solid surface to the logarithm of Po of these probes. This new approach leads to a simple and accurate determination of γSD since vapor pressures of liquids are easily available data. Nevertheless, the method based on this relationship fails for determining the specific energy of adsorption of polar probes on a solid surface. © 1990.