Surface Forces in Wetting Films

Reviewed are theoretical and experimental results of Russian and foreign researchers of the surface forces acting in asymmetric system, wetting films contacting with the condensed phase on the one side and with the gaseous phase or own vapor on the other side. Wetting films play an important role in such phenomena as wetting and spreading, flotation, polymolecular adsorption, evaporation of liquids from porous bodies, and capillary condensation. Disjoining pressure isotherms of wetting films determine the wetting conditions and the values of forming contact angles. The mechanisms of film stability, rupture, and coalescence are discussed based on the theory of surface forces. The properties of the films of nonpolar liquids and liquid mixtures; polymolecular adsorption films of polar liquids; as well as wetting films of aqueous electrolyte solutions, surfactants and polymers are analyzed systematically.