TEMPERATURE EFFECT ON THE ADSORPTION OF IONIC SURFACTANTS AT WATER/HEXANE INTERFACE FROM MICELLAR SOLUTIONS.

THE ADSORPTION BEHAVIOR OF DODECYLAMMONIUM CHLORIDE (DAC) AND SODIUM DODECYL SULFATE (SDS) AT THEIR AQUEOUS MICELLAR SOLUTION/HEXANE INTERFACE HAS BEEN STUDIED BY MEASURING THE INTERFACIAL TENSION AS A FUNCTION OF TEMPERATURE AT CONCENTRATIONS AROUND THE CRITICAL MICELLE CONCENTRATION (CMC). THE DERIVATIVE OF THE INTERFACIAL TENSION WITH RESPECT TO TEMPERATURE HAS BEEN OBSERVED TO CHANGE ABRUPTLY AT THE CMC AND VERYLITTLE THEREAFTER WITH INCREASING CONCENTRATION IN A LIMITED RANGE ABOVE THE CMC. BY APPLYING THE THERMODYNAMIC TREATMENT OF ADSORPTION FROM MICELLAR SOLUTION DEVELOPED PREVIOUSLYTO EXPERIMENTAL RESULTS, THE ENTROPY CHANGES ASSOCIATED WITH THE ADSORPTION OF DAC AND SDS FROM MONOMERIC STATE AND FROM MICELLAR STATE AND THE CORRESPONDING ENERGY CHANGES ARE CALCULATED.