(366f) The Effect of Solute-Solute Interactions On Diffusion in Gels and Micelle Solutions

Many controlled release systems in food and medical applications, as well as bioseparation methods, occur under conditions where solute-solute interactions have a significant impact on rates of diffusion.  To improve the current understanding of these processes, a rigorous application of the principles of fluid mechanics and mass transfer is essential.  In polymer gels such as agarose, the presence of gel fibers screens hydrodynamic interactions between solutes, while enhancing non-hydrodynamic interactions because of volume exclusion.  The result is in increase in the effect of concentration on rates of diffusion, relative to what is present in gel-free colloidal solutions.  As a second system, we also consider the diffusion of hydrophobic solutes in micelle solutions.  In such solutions, multicomponent effects are not negligible:  a gradient in surfactant concentration can induce or even eliminate fluxes in the hydrophobic solute.