Determination of the Diffusion Coefficients of Micelle and the First CMC and Second CMC in SDS and CTAB Solution

A new electrochemical method is showed for study of physical chemistry character of surfactant systems, and particularly determination of second CMC. The diffusion coefficients of SDS and CATB micelles with different shapes are determined by cyclic voltammetry without any probe and the first CMC and second CMC are obtained from the intersections of diffusion coefficients vs concentration curve (first CMC and second CMC are 8.0 x 10(-3)mol.L-1 and 5.6 x 10(-2)mol.L-1 for SDS, 8.9 x 10(-4) and 2.1 x 10(-2)mol.L-1 for CTAB).