Electrohydrostatic adhesion of rigid-planar electrodes

The electrohydrostatic adhesive force of a poorly conducting fluid filling the gap between two electrodes is studied both theoretically and experimentally. A vertical load electrode of mass mm is grounded and the other load-bearing electrode is held at a constant potential. The conditions for which the vertical force F=mgF=mg, where gg is the gravitational acceleration constant, may be supported by electrohydrostatic adhesion is determined by considering electrical and hydrostatic stress contributions to an overall force balance along the air–liquid interface. The results are compared with experiments performed using castor and silicone oils with gap spacing on the order of 100–500μm, at electric potentials on the order of 1 kV, currents on the order of 10μA and vertical forces on the order of 0.01–0.1 N. The experiments and theory show good agreement.