Fully developed contact angle change of a droplet in liquid actuated by dielectric force

Abstract

The non-saturation phenomenon of contact angle change of a nonconductive droplet in an immiscible dielectric liquid with iso-density is demonstrated using the dielectric force due to the difference of the two dielectric constants. The concentric electrode design permits the dielectric force exerted at various contact angles. The droplet fully develops from 22° to 176° (nearly spherical) in contact angle as the voltages tuned from 0 to 215 V rms. The contact angle change was found to behave almost linearly with respect to voltage by experiments. The dielectric force in the liquid/liquid interface was further simulated at the aspects of energy distribution, force distribution, and electric fields, found in a good agreement with experimental results. © 2012 American Institute of Physics.