Molecular dynamics study of the structure and mechanism of formation of molecular associates in aqueous solutions of surfactants

Abstract

The process of micelle formation in an aqueous solution of the surfactant was simulated by the computer experiment. It was established by the molecular dynamics method that micelles are formed through the formation of premicellar associates of the surfactant. The practical absence of an attraction between single molecules of sodium pentadecyl sulfonate (SPDS) and premicellar associates dissolved in water was shown for a SPDS—water system. The function of the radial distribution of Na+ counterions towards polar groups of SPDS molecules in water and on the surfaces of micelles and premicellar associates was studied by the molecular dynamics method. The presence of dissociated and non-dissociated polar groups of the SPDS molecular on the micelle surface was found. The data obtained are consistent with the existence concepts on micelle formation processes.