MIXED MICELLES OF SDS AND SODIUM CHOLATE. A NUCLEAR MAGNETIC RESONANCE DIFFUSION AND RELAXATION STUDY

Abstract

A nuclear magnetic resonance diffusion and relaxation investigation of the mixed micellar system sodium dodecylsulfate (SDS)/sodium cholate (SC) is presented. The concentration of SDS is kept constant at 15 mM and the concentration of SC is varied up to a total SC concentration of 100 mM. The diffusion coefficients of SDS and SC and the ²H relaxation rates of specifically ²H labeled SDS are measured. These quantities are used in the description of the distribution of the two surfactants in the various environments (as monomers in solution and associated into micelles). A theoretical framework based on the Bragg-Williams model is used to qualitatively describe the data.