INTERACTION ENERGIES OF ORGANIC MOLECULES WITH RUTILE AND GRAPHON SURFACES FROM HEATS OF IMMERSION

Abstract

The heats of immersion of rutile in a series of short chain organic liquids are found experimentally to be an approximate linear function of the dipole moment of the wetting liquid. The significance of the relation is discussed in terms of the polar van der Waals force contribution which is primarily dependent on dipole moment. The average distance of approach of a dipole to the rutile surface and the effective surface force field extending from the rutile surface are calculated.The net adsorption energy, which is calculated directly from heat of immersion data, is related to the energy contributions resulting from the various polar and nonpolar van der Waals forces active in the adsorption process: These energy contributions which make up the total adsorption energy are calculated for the interaction of an alcohol and a hydrocarbon with both a heteropolar (rutile) and a homopolar (Graphon) surface. On the basis of the results obtained, the effects of chain length and functionality of the liquids on the heat of immersion are discussed.