MICELLIZATION AND SUPERFICIAL ACTIVITY OF N-ALKYLTRIMETHYLAMMONIUM BROMIDES IN WATER-ORTHOPHOSPHORIC ACID-MEDIUM

Measurements of superficial tension of n-alkyltrimethylammonium bromid es in air/water-orthophosphoric acid interface have been made by ''str ipping method''. Data were evaluated by approximation to the Von Szysz kowski equation. Thermodynamic parameters as (Gamma(max), F, A, B, Del ta G(A) degrees, Delta G(M) and CMC) at different concentrations of or hophosphoric acid (0 at 3 M) are calculated. The CMC values of the hom ologous series in relation to the chain length were determined. They s howed a good correlation with the Klevens equation. A minimum of CMC a nd (-Delta G(M)) was observed for the n-octadecyltrimethylammonium bro mide, which has been attributed to the cosolvant effect and the change of medium properties.