Repeptization and the theory of electrocratic colloids

Abstract

The coagulation and the repeptization of electrocratic colloids can be treated in one theory provided that the appropriate boundary conditions are chosen. From this version of the DLVO theory it follows that for each sol there exists a critical value Z∞c of the double layer parameter Z∞, Z∞ = zeδ/kT. A sol is stable, and flocs can repeptize if Z∞ > Z∞c. For Z∞ < Z∞c the traditional DLVO theory is obtained. Some examples are given to illustrate this concept. In the appendix the interaction of double layers with a constant charge is related to that at a constant potential.