Effective Self-Diffusion Coefficients of Ions in Sodium Dodecyl Sulfate Micellar Solutions

The effective self-diffusion coefficients of ions in premicellar and micellar solutions of sodium dodecyl sulfate are measured by the NMR self-diffusion method at 40 degrees C. The obtained regularities are explained using a proposed model that takes into account the possible surface diffusion of counterions bound with micelles. This effect is shown to markedly influence the charge transfer in micellar solutions. Based on the results obtained, the self-diffusion coefficients of bound Na+ counterions are estimated and the causes and ranges of their variations are indicated.