Electroviscous forces

Abstract

The general theory of electroviscous forces between charged colloidal particles is presented. This theory has been simplified using the squeezing-flow approximation for the case of the interaction between two uniformly charged discs. The total friction coefficient, including the contribution from the electroviscous force, was calculated. Using the Derjaguin approximation, we calculated the relative friction coefficient for two charged spherical particles, which was then used to obtain the theoretical rates of the coagulation and/or deposition process. The theory was compared with experimental data. Good agreement was obtained for coagulation, while a significant discrepancy for deposition was found, indicating that additional effects, not accounted for in our theory, should be considered.