WATER ON HYDROPHOBIC SURFACES

ABSTRACT Highly polar liquids (water, ethanol, FA, DMFA, DMSO) on silicate surfaces covered with alkylammonium ions are aggregated in clusters. This tendency increases with the chain packing density. Salts sensitively influence the cluster formations. In water and ethanol the effects follow the Hofmeister series in the opposite direction: The amount of adsorbed water increases, the amount of adsorbed ethanol decreases with increasing structure breaking. The adsorption of DMSO is sharply reduced at very low concentrations of breaking salts. A model is proposed relating the hydrophobic/hydrophilic character of the surface to the clustering of the water molecules between the alkyl chains.