Electrowetting Actuation PDF Print E-mail
Written by Sina Alavi   


Electrowetting is a phenomenon in which the contact angle of a polarizable/conductive liquid drop is manipulated by the means of applying an electric potential between the drop and the electrode on which the drop is placed. In this manner, the electrode must be coated with an insulator (dielectric) covered subsequently by a hydrophobic coating. This phenomenon can be used to manipulate and move liquid droplets in digital microfluidics and Lab-On-A-Chip technologies. It can also be used to move the droplets to a hot-spot and transfer heat to avoid the concentration of heat in a very small area on a transistor or integrated circuit.

Using a PCB-based electrowetting device, the contact angle of a droplet is manipulated under various values of applied AC voltages. Also an in-house numerical code is developed to simulate electrowetting using VOF method. The images taken from the experiments and simulations are compared. Experiments are performed both in air and silicone oil environments.




Calculated images (a) and experimental results for (b) air and (c) silicone oil environments for a 20 μL mercury droplet under the effect of various applied 50 Hz AC voltages. Numerical results involve the electric potential contours and the black line shows the free surface of the droplet.