Scattering properties of salt-free wormlike micellar solutions

Static and dynamic light scattering and conductivity experiments were carri ed out on salt-free aqueous micellar solutions of cetyltrimethylammonium n- hexane sulfonate (CTAC(7)SO(3)) and cetyltrimethylammonium n-heptane sulfon ate (CTAC(7)SO(3)) as a function of surfactant concentration. This study co nfirms the analogy between the behavior in the semi-dilute regime of elonga ted micellar systems and "classical" polyelectrolyte solutions. Time-resolv ed scattering experiments performed after a variation of concentration from about twice the overlap volume fraction Phi* to less than half of it revea led the existence of a structural relaxation with a characteristic time of several hours.