Potentiometric determination of adsorption isotherms of dodecyldimethylamine-N-oxide onto laponite

Adsorption isotherms of dimethyldodecylamine-N-oxide (DDAO) onto laponite were determined by potentiometry, using a surfactant-specific electrode. The isotherms were obtained at pH 7; 8 and 9, and at various NaCl concentrations. The stability of laponite in these conditions was evidenced. All isotherms are mingled in these conditions and the level of adsorption of the non-ionic surfactant is found to be much higher than that of its cationic homologue, dodecyltrimethylammonium (DTA+).