DETERMINATION OF THE DIFFUSION COEFFICIENT FOR SDS MICELLE WITH DIFFERENT SHAPE AND THE EFFECTS OF ETHANOL BY CYCLIC VOLTAMMETRY WITHOUT PROBES

摘要

Micelle diffusion coefficient of SDS with different micelle shape in aqueous and water-ethanol solutions are determined by cyclic voltammetry without any probe. The diffusion coefficient decreases with as increasing SDS concentration. The first critical micellar concentration is 8.0x10(-3) mol . l(-1) corresponding to the transformation from premicelle to spherical micelle. The second critical micellar concentration is 5.60x10(-2) mol . l(-1) and corresponding to transformation from spherical micelle to rod-like micelle. The less the weight ratio of SDS to ethanol is, the larger the diffusion coefficient is. The influence of added water to the micelle solution is almost the same for SDS-ethanol-H2O system with different micelle shape. Mechanism of electrochemical reaction for SDS at platinum electrode is discussed as well. [References: 27]