Semianalytical study of hemispherical meniscus oscillation with an anchored edge on a conductive flat plate under an ac electric field

Abstract

This paper presents an experimental observation and a semianalytical simulation of the oscillations of an anchored hemispherical liquid meniscus on a conductive flat plate under an ac electric field. For the simulation, the liquid is assumed to be an incompressible, inviscid, and perfectly conductive fluid in a zero-gravity environment. The mutual interaction between the electric field and the hydrodynamics is iteratively solved. As a result, the simulation can follow the oscillating meniscus shapes and contours of the electric field outside the meniscus according to the applied frequency. The velocity profile of the liquid inside the meniscus is also presented. The present theory can be used to predict the oscillation shape of a liquid droplet on a plate with a certain applied frequency. The simulated oscillation shape is in agreement with the experimental result. The effects of the liquid density, the liquid surface tension, and the radius of the hemispherical meniscus on the oscillation are investigated. Then the oscillation of the drop on hydrophobic and hydrophilic substrates is also experimentally studied. Furthermore, we investigated the effects of the applied electric field on the coffee stain effect while the droplet is drying. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3556610]