Diffusion coefficients of micelles composed of fluorocarbon surfactants with cyclic voltammetry

Cyclic voltammetry of(ferrocenylmethyl)trimethylammonium bromide (FcTAB) wa s applied on anionic micelle systems in order to reveal the solution proper ties of micelles composed of fluorocarbon surfactants. Diffusion coefficien ts of FcTAB decreased with micelle formation because the cationic FcTAB dif fuses together with micelles. The diffusion coefficient abruptly decreased with the addition of sufficient salt, suggesting an increase in micelle siz e and a transition of micelle shape. The diffusion coefficient for mixed mi celles composed of fluorocarbon and hydrocarbon surfactants decreased consi derably compared to those for their single surfactant systems. The micelle size of fluorocarbon surfactants, especially for lithium 1,1,2,2-tetrahydro heptadecafluorodecyl sulfate, significantly depended on the salt concentrat ions and the compositions of the mixtures. Cyclic voltammetry is a simple a nd useful method to evaluate the micelle diffusion coefficients of fluoroca rbon surfactants which can hardly be estimated by dynamic-light-scattering measurements.