Electrowetting on dielectric (EWOD) of sessile microdroplets containing gold nanoparticles

Our electrowetting set-up consists of a bottom copper electrode coated with a thin insulating layer of dielectric (uncured polydimethylsiloxane) and a platinum wire upper electrode in contact with the sessile gold nanofluid droplet sitting on the dielectric layer. EWOD experiments are conducted with the following concentrations of gold nanofluid (in µM): 0.5, 0.33, 0.25, 0.05, 0.01, 0.005 and control fluid. Results show enhanced electrowetting response for microdroplets containing higher concentrations of gold nanoparticles. The specific capacitance is calculated for each concentration and is found to increase with increasing concentration, in agreement with an electromechanical model for the electrowetting phenomena.