On the surface thermodynamics of a two—component liquid-vapor-ideal solid system

Abstract

The surface thermodynamics of a two—component three—phase solid—liquid—vapor system is considered. Under the assumption that the solid is ideal, i.e., smooth, homogeneous, rigid, and has no appreciable vapor pressure, it is shown that an equation-of-state type of relation exists between the solid—vapor, the solid—liquid, and the liquid—vapor interfacial tensions. The existence of this relation in conjunction with Young's equation makes it, in principle, possible to determine the solid-vapor and the solid—liquid interfacial tensions from contact angles. A test is described which, on the basis of contact angle data for a solid in contact with several liquids, allows one to decide whether or not adsorption of the vapor of the liquids on the solid is appreciable.