Investigation of effective interface potentials by electrowetting

¹ Laboratoire de Spectrométrie Physique (Unité mixte de recherche CNRS (n°5588) & Université Joseph Fourier Grenoble 1.) , BP 87 38402 St. Martin d'Hères Cedex, France
² Laboratoire de Physique de l'ENSL (Unité mixte de recherche CNRS (n°5672) & Ecole Normale Supérieure de Lyon.) 46 allée d'Italie, 69364 Lyon Cedex 07, France

Received: 28 February 2002
Accepted: 10 July 2002

Abstract

We study a situation where the complete wetting of a dielectric solid by a dielectric liquid, in a conducting surrounding, is altered by the application of an electrical potential difference. Calculations predict a dewetting transition towards pseudo-partial wetting. More generally, in a pseudo-partial wetting situation (pre-existing or electrically induced), the mesoscopic film coexisting with the macroscopic droplet is expected to be thinned by the electrostatic pressure in a way that is directly related to its effective interface potential. This points out a possibility to tune the thickness of a fluid film in a nanometric regime.