SEGMENTAL ADSORPTION ENERGIES FOR POLYMERS ON SILICA AND ALUMINA

Segmental adsorption energies for polymers on inorganic solids can be determined from adsorption/desorption transitions in binary solvent mixtures. These transitions were measured for various polymer/solvent/substrate systems by thin-layer chromatography. Polymers with either phenyl, ether, or ester groups were classified according to their adsorption strength on both silica and alumina. A consistent trend with respect to the adsorption energy for the different polymers was observed for both substrates. Polymer chains with larger alkyl side groups or more -CH2- groups between ether groups in the backbone have a lower adsorption energy. The adsorption energy for each individual polymer is higher on the silica surface than on the alumina surface. For the polymers studied, the main contribution to the work of adhesion on silica with respect to vacuum is due to dispersive interactions.