Wormlike micelles as equilibrium polyelectrolytes: Light and neutron scattering experiments

We demonstrate that aqueous solutions of giant polymer-like nonionic micelles doped with small amounts of ionic surfactants serve as ideal model systems for equilibrium polyelectrolytes. We report systematic light and neutron scattering investigations of the effect of ionic strength, doping level, and total concentration on the static properties of dilute and semidilute micellar solutions. In dilute solutions, we observe a dramatic influence of (intramicellar) electrostatic interactions on the micellar flexibility, and the results are in close agreement with Monte Carlo simulations. We also analyze the effect of electrostatic contributions to intermicellar interactions and micellar growth. In the semidilute regime, strong long-range interactions between micelles occur at low ionic strength and induce liquidlike ordering, and the resulting structure factor peak exhibits the same concentration dependence as previously observed for polyelectrolytes.