Electrokinetic properties of metal-dielectric interfaces

Using an optical interferometric method capable of determining mechanical displacements in the nm to pm range, measurements are reported of displacements resulting from electrically induced strains in a variety of metal-dielectric interfaces. The dielectrics include aqueous electrolytes, glycol, glycerol, silicone oil and polyethylene. The displacements are shown to conform to the predictions of the Lippmann equation. The implications of these measurements are discussed and are believed to be particularly important in the initiation of failure in polymeric insulation at high voltage. The results also suggest possible device applications based on the electromechanical, piezoelectric properties of these interfaces.