Electric Double Layer: Helmholtz Model

This lecture covers the concept of the electric double layer (DL) on charged surfaces in solution, focusing on the Helmholtz model. It explains how surfaces become charged in solutions, attracting counterions to form the DL. The lecture discusses the assumptions and limitations of the Helmholtz model, neglecting ion diffusion. It also introduces the Gouy-Chapman model, which considers ion thermal motion, leading to a diffuse DL. The Stern model, combining the Helmholtz and diffuse layers, is presented, along with the concept of the Outer Helmholtz Plane. Various calculations and examples related to the DL, Debye length, and surface potential are discussed, emphasizing their importance in understanding electrokinetic phenomena.