Interpreting Aggregation-dispersion of Aqueous Colloidal Dispersion Based on DLVO Theory with Focusing on Critical Coagulation

Abstract

This article introduces the interpretation of critical coagulation concentration（ CCC） on the basis of DLVO theory and zeta potential. We begin with the overview of DLVO theory with emphasizing how we get its analytical expression, and then mention electrophoresis and zeta potential as a tool to characterize the charging of colloidal particles. Further, we describe recent interpretations of CCC using DLVO theory. That is, while DLVO theory does not consider ion specific effects, DLVO theory with effective charge density from zeta potential can rationalize ion-species dependent CCC. Also, the Schulze-Hardy empirical rule, which suggests CCC is strongly related to counter-ion valence, can be explained by the combination of DLVO theory for low electric potential and effective surface charge density. Well-known assumption that the surface potential is extremely high is probably incorrect. This means that the measurement of zeta potential at different solution conditions and the development of theoretical model predicting zeta potential are crucially important. At last, we mention the inverse Schulze-Hardy rule is confirmed experimentally and theoretically.