A novel electrode shape for electrowetting-based microfluidics

This work presents a combined numerical and experimental study to investigate the effect of electrode shape in electrowetting-based microsystems. A new electrode shape is proposed which provides a uniform actuation force at the contact line as well as overlap between the adjacent electrodes. The onset of actuation and droplet mobility on electrode arrays have been investigated. The numerical method is based on volume of fluid technique to track the 3-D interface along with a Laplace equation solver to calculate the electric field in the domain. Furthermore, the dynamic behaviour of three-phase contact line is modeled using molecular-kinetic theory. Validation experiments were carried out to characterize the droplet actuation by various electrode shapes. The superior performance of the new electrode shape is demonstrated by comparing the droplet velocity and deformation, as well as contact angle distribution of those of a simple flat electrode.