ABSTRACT

An important role in surface phenomena is played by the surface potential of solids, which is created by the cumulative effects of atoms of the solid on molecules of the liquid and vapour near the boundary of the solid. Coexisting bulk phases are separated by partition surfaces, representing the layers of finite thickness, in which at least one of the parameters of the system changes in the direction from one phase to another in a finite amount. The Gibbs phase rule is derived from the conditions of the thermodynamic equilibrium of multicomponent mixtures which in isolated system consist of the identical conditions for the existence of each of its phases. Below the process of stratifying of the adsorbate in the micro-nonuniform systems is considered from the standpoint of molecular interpretation of the thermodynamic phase rule on the basis of the molecular–statistical theory of adsorption.