Aqueous micellar solutions of dodecyl and hexadecyltrimethylammonium bromides, hexade cylpyridinium bromide and chloride, domiphen bromide ((dodecyldimethyl N 2 phenoxyethyl)ammonium bromide), hexadecyltriphenylphosphonium bromide, and sodium dodecyl sulfate have been investigated using dynamic light scattering. A local increase in the diffusion coefficient has been discovered for all ionic surfactants at concentrations higher than the first critical micelle concentration (CMC1). It has been shown that, at the same alkyl chain length and counterion nature, the increase in the diffusion coefficient with surfactant content becomes more pronounced with a reduction in CMC1. The concentration dependences of
the diffusion coefficients have been explained in terms of a previously proposed theory formulated for ideal micellar systems. The existence of the local minimum in the diffusion coefficient near CMC1 has been shown to be a general regularity for binary surface active electrolytes.