Tunable micro liquid droplets using dielectric force

The actuation of micro liquid droplets using dielectric force was demonstrated on a patterned concentric electrode by experiments and simulation. The strength of electric field around the contact line was maximum when the voltage applied. When the voltage changed from 0 V to 200 V, the contact angle of the droplet varied from 90° to 126° for the electrode with a diameter of 500 µm and varied from 100° to 125° for the one with a diameter of 700 µm, respectively. From observation of dynamic response of liquid droplet, electrical pressure dominates the droplet shape nearby the contact line within a period of 30 ms. The mechanical equilibrium of droplet shape will occur behind electrical dynamic response. Results indicate 500µm and 700µm diameter droplets may be tunable and well positioned in this device.