The Properties of Liquid Phase Embryos at the Intersections of Plane Solid Surfaces

Abstract

In order to calculate the probabilities of nucleation of liquid droplets at different types of site on a solid surface, the properties of embryonic droplets which may exist in complete thermodynamic equilibrium at those sites must be known. The general properties of liquid embryos formed on a plane solid surface, or at lines or points of intersection of plane solid surfaces, are considered. It is shown that, although an edge free energy associated with the boundary line may substantially affect the properties -of embryos at small contact angles, the effect is probably not large, for embryos of the sizes of interest, when the contact angle is larger than about π/4. The areas, volumes, total surface free energies, and free energies of formation are found for embryos at these sites as functions of the contact angle, any edge free energies being neglected. The extension to the formation of bubbles at plane solid surfaces in a pure liquid is indicated. The results are applied in a following paper to the kinetics of condensation of a vapour at an imperfect crystalline surface.