van der Waals dispersion force contribution to works of adhesion and contact angles on the basis of macroscopic theory

The macroscopic theory of van der Waals dispersion forces is used to derive equations for the work of adhesion and contact angle of a liquid on a solid in the presence of a thin layer between them. Approximate expressions are also derived in terms of Hamaker constants and surface energies. The results obtained are expected to hold whenever dispersion forces alone are operating between the media.The surface tensions of a number of saturated hydrocarbons are calculated on the basis of macroscopic theory and the results are found to agree well with measured values.