Study of Mixed Micellar Aqueous Solutions of Sodium Dodecyl Sulfate and Amino Acids1

摘要

Thermodynamic properties of sodium dodecyl sulfate (SDS) in micellar aqueous solutions of L serine and Lthreonine were determined by fluorescence spectroscopy and dynamic light scattering tech niques. The values of Gibbs free energy, enthalpy and entropy of the process of micelle formation were cal culated using the critical micelle concentration and degree of dissociation. Changes in critical micelle con centration of SDS with the addition of amino acids were examined by both conductivity and pyrene I1/I3 ratio methods at different temperatures. The pyrene fluorescence spectra were used to study the change of micropolarity produced by the interaction of SDS with amino acids. The aggregation behavior of SDS was explained in terms of structural changes in mixed solutions. The data on dynamic light scattering suggest that size of SDS micelles was influenced by the presence of amino acids.