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 90deg to 126deg for the electrode with a diameter of 500 mum and varied from 100deg to 125deg for the one with a diameter of 700 mum, 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 500 mum and 700 mum diameter droplets may be tunable and well positioned in this device.