ELECTROCHEMICAL INVESTIGATIONS IN MICROEMULSION MEDIA .1. METHYLVIOLOGEN REDUCTION

The electrochemical reduction of methylviologen was investigated in cationic, anionic, and nonionic microemulsions. The reduction takes place in two reversible single-electron-transfer steps. Adsorption of the neutral form of methylviologen on the electrode surface observed in aqueous solutions is eliminated in microemulsions. The half-wave potentials for both reduction steps and the diffusion currents depend on the type and composition of the microemulsion. The observed results are explained on the basis of electrostatic interactions of methylviologen dication and cation radical with the surfactant and the solubilization of the hydrophobic neutral form in the nonaqueous domains of the microemulsion. © 1990, American Chemical Society. All rights reserved.