Forces between hydrophobic surfaces in aqueous electrolyte and surfactant solutions containing common air-borne impurities

The forces between surfaces made hydrophobic either by surfactant adsorption or by chemical methylation are not describes by DLVO theory when the aqueous solutions contain air-borne organic contaminants. Even when the bulk concentration of these hydrophobic contaminants is extremely low they readily adsorb onto hydrophobic surface sites and significantly affect the Interaction forces out to distances of 250 nm.