EFFECT OF SUPPORTING ELECTROLYTE CONCENTRATION ON THE ELECTROCHEMICALREACTION OF REDOX-ACTIVE SURFACTANT MICELLES IN AQUEOUS-SOLUTIONS

The effect of NaCl concentration on the redox potential of ha-ferrocen ylundecyl-omega-hydroxy-polyoxyethylene (FPEG) micelles has been studi ed in aqueous solutions. With increasing NaCl concentration, the anodi c half-wave potentials E-1/2 of cyclic voltammograms of the aqueous so lutions shift to higher potential, and the peak currents of the cyclic voltammograms decrease. The results are discussed in terms of thermod ynamics of the micelle formation. An equation which interprets the cor relation between the E-1/2, the salt concentration, diffusion coeffici ent of the micelle D-M, and the aggregation number m, has been derived . The changes in D-M and m with NaCl concentration do not explain the change in the value of E-1/2. The decrease in the equilibrium constant for the micelle-disruption K-d with increasing NaCl concentration aff ects the redox-potential of the FPEG micellar solutions. (C) 1997 Else vier Science S.A.