KINETICS ASSOCIATED WITH THE CHANGE OF THE NUMBER DENSITY OF MICELLESIN SOLUTION

The kinetics of fusion/fission of micelles, in the transition range be tween spherical and elongated micelles, has been investigated using an approach similar to those of Aniansson and Kahlweit. On the assumptio n that the relaxation process associated with the exchange of surfacta nt between micelles acid solution is very fast and that the creation o f large aggregates by stepwise association of monomeric surfactants is slow, the frequency of relaxation was found to depend on the average collision frequency, the micelle length distribution, and the number d ensity of micelles. Well above the cmc, the relaxation frequency is eq ual to the ratio of the average fusion rate over the derivative of the aggregate number with respect to the number of surfactant molecules i n micelles. The obtained expression applies to many length distributio ns from short micelles with a low or a large polydispersity to elongat ed micelles. Numerical simulations of the variation of the relaxation frequency with surfactant concentration are given for three different micellar energy distributions.