The electrokinetic properties of metal-dielectric interfaces

The authors describe a sensitive interferometric system capable of measuring mechanical displacements at dielectric-metal electrode interfaces when subjected to alternating electric fields as weak as 0.1 V mm^-1. They show that, for a number of dielectric-metal interfaces, the displacements have a significant component at the fundamental frequency of the applied field, f, and, when the field is low, a weaker component at 2f. They suggest that the results can be explained most conveniently in terms of the Gibb´s adsorption equation for the interface which relates the interfacial energy to the electrical properties of the double layer established at the dielectric-metal contact. The implications of these electrokinetic results for situations of practical importance will be discussed