This document discusses the stabilization of emulsions via electrostatic forces. It defines emulsions as dispersions of one liquid in another immiscible liquid, and describes the electrical double layer that forms around dispersed droplets consisting of surface charges and layers of counterions. The document outlines DLVO theory, which states that emulsion stability is determined by a balance of attractive van der Waals forces and repulsive electrostatic forces. It also discusses how zeta potential measurement relates to stability, and how pH and ionic strength can affect zeta potential and thus the stability of emulsions.