Study on intermicellar interactions and micellar size in aqueous solutionsof sodium taurocholate by measurements of collective diffusion and self-diffusion coefficients

Aqueous micellar solutions of sodium taurocholate (NaTC) have been studied by using quasi-elastic lightscattering (QELS) and H-1 pulse-gradient-stimul ated-echo NMR (PGSTE-NMR). The collective and selfdiffusion coefficients ha ve been obtained as a function of NaTC concentration (0.05-0.20 M) and the ionic strength of the solution (0-0.8 M NaCl added). The comparison of the two techniques' data in each solution has been performed in the context of micellar growth and intermicellar interactions. The model of monodisperse B rownian particles with hydrodynamic interaction and hard core repulsion giv es rise to a satisfactory agreement with the experimental data. The transla tional diffusion coefficient of the single micellar aggregate has been calc ulated for each solution. The size of the micellar aggregates depends on th e ionic strength and bile salt concentration.