The static dielectric constant of a colloidal suspension

We derive an expression for the static dielectric constant of the colloidal suspensions based on the electrokinetic equations. The analysis assumes th at the ions have the same diffusivity, and that the double layer is much th inner than the radius of curvature of the particles. It is shown that the d ielectric increment of the double-layer polarization mechanism is originate d from the free energy stored in the salt concentration inhomogeneity. We a lso show that the dominant polarization charges in the theory are at the el ectrodes, rather than close to the particles. (C) 2001 American Institute o f Physics.