Lecture 22: Stern Layer, Zeta Potential, DLVO Theory, non-DLVO Interactions and Charge Measurements

The Gouy-Chapman model is the least complicated quantitative description of the diffuse layer. In this third and final lecture of Chapter 8, we augment this model to consider a surface layer of counter-ions known as the Stern layer. With this modification, we can rewrite the electric double layer model in terms of the zeta potential, defined as the electric potential outside the Stern layer. From here, we introduce the DLVO theory in a more usable form. We will also review non-DLVO interactions, and the chapter ends with an overview of charge measurements used to characterize colloids and suspensions.