RHEOLOGICAL ELECTROKINETIC PHENOMENA IN A SINGLE CAPILLARY

A numerical simulation of rheological electrokinetic phenomena in a rectangular capillary slit is reported. The theological state of the vicinity water in the capillary is based on the Babchin-Piliavin-Levich model of the viscoelectric effect. The electrical field of the diffuse double layer is considered as the cause for the non-Newtonian behaviour of the interface water layers. A special numeric procedure is suggested to solve the closed system of equations which describe the generalized flows through the capillary. The solution for a particular case (10-5 N KCl water solution, 2 μm x 0.6 cm x 1 cm capillary slit) is presented and discussed. An approximate linear relation between the driving forces and the total current and volume fluxes is obtained and used to determine the phenomenological kinetic coefficients. The electrokinetic ζ-potentials which are functions of the surface charges (potentials) and external conditions are predicted. It is found that ζ-potentials may be different for different electrokinetic experiments. The results are compared with predictions based on a classical viscous flow model. © 1979 Academic Press, Inc.