Molecular interpretation of electrokinetic potentials

A discussion is given of the electrokinetic, or ζ-potential in terms of the slip process and the composition of the electric double layer. Electrokinetically, only the outer parts of double layers are active. The existence of a stagnant part is generally observed for aqueous solutions adjacent to solid surfaces. It is claimed that this stagnancy is caused by the spontaneous structuring of fluids near solid surfaces. Hence, it is a ubiquitous phenomenon and the thickness of the stagnant layer does not significantly depend on the wettability and the surface charge of the surfaces.