ENORMOUS CONCENTRATION-INDUCED GROWTH OF POLYMER-LIKE MICELLES

We report a detailed analysis of the effect of concentration on the mi cellar size, the static structure factor at q-->0, S(0), and the stati c correlation length xi(8) measured with static light scattering in aq ueous solutions of the nonionic surfactant hexaethylene glycol n-hexad ecyl monoether (C(16)E(16)) which forms giant polymerlike micelles in water. Measurements were performed at two different temperatures in or der to test for possible contributions from critical scattering which could become important in the vicinity of the critical point. We find no measurable temperature dependence for the apparent molecular weight and the correlation length of the micelles for the given range of con centrations and temperatures. We demonstrate that the concentration de pendence of the micellar size distribution and intermicellar interacti on effects can be combined in a self-consistent way using results from conformation space renormalization group theory originally developed for semidilute polymer solutions. Our results indicate a much stronger micellar growth than that previously predicted by the theoretical mod els for micelle formation.