A diffuse aggregation of positive and negative electric charges surrounding a suspended colloidal particle which aids in maintaining its stability. According to the Gouy-Freundlich theory, advanced about 1920, a close-packed array of charges is attached to the surface of the particle while a diffuse layer of charges of opposite sign extends into the liquid. The particle is electrically neutral. There is an electrokinetic potential gradient across the double layer that is called the zeta potential. The diagram is an approximation of this phenomenon. Modifications of this theory have been introduced in recent years, notably by Derjaguin and Landau and by Verwey and Overbeek (DLVO theory).See Zeta Potential.