INTERFACIAL RHEOLOGY AND KINETICS OF ADSORPTION FROM SURFACTANT SOLUTIONS

A theoretical approach to the diffusion controlled kinetics of adsorpt ion on the expanding interface of surfactant solutions is developed an d compared with the experiment. This approach being an analogue of von Karman's approach to the hydrodynamic boundary layer is applicable to both submicellar and micellar surfactant solutions under large deviat ions from equilibrium. The partial differential equations of the conve ctive diffusion are reduced to a set of ordinary differential equation s of first order and algebraic equations. This simplifies the numerica l computations and enhances the interpretation of the experimental dat a. Dynamic surface tension data for solutions of sodium dodecyl sulfat e obtained by the maximum bubble pressure method are interpreted. Reas onable results for the diffusivity of monomers and the rate constant o f micellar disintegration have been obtained. A local approach to inte rfacial rheology is briefly considered. The applicability of this appr oach to studies of visco-elastic dilational properties of adsorption l ayers from low molecular surfactants and proteins is demonstrated.