Electric field induced deformation of hemispherical sessile droplets of ionic liquid

Sessile droplets of an ionic liquid with contact angles close to 90° were subjected to an electric field E = V/w inside a capacitor with plate separation w and potential difference V. For small field induced deformations of the droplet shape the change in maximum droplet height, Δh = h(E) – h(0), was found to be virtually independent of the plate separation provided that w > 3h(0). In this regime a scaling law obtains Δh α E2r2, where r is the constant droplet radius, in agreement with the asymptotic predictions of Basaran and Scriven (J. Coll. Int. Sci. 140, 10, 1990).