EFFECTS OF LATERAL INTERACTION ON THE ADSORPTION OF SURFACTANTS AT THE AIR-WATER-INTERFACE

The adsorption of CTAB and AOT at the air-water Interface has been ana lyzed using the Gibbs and Frumkin isotherms. at sufficiently high surf actant concentrations, the area occupied by each molecule was evaluate d to be 50 and 70 Angstrom(2) for CTAB and BOT, respectively. The late ral interaction coefficient between the adsorbed AOT species was found to be higher than that between the adsorbed CTAB species at the same degree of surface coverage. This was attributed to the presence of dou ble hydrocarbon chain in case of AOT while CTAB has a single chain, Th e increase in lateral interaction was found to enhance the adsorption where the standarad free energy of adsorption of BOT was found to be l ower than that of CTAB.