Anisotropic spreading of droplets on striped electrodes

Anisotropic spreading of droplets on a heterogeneous solid surface is important for fundamental research and industrial applications. Compared to structurally and chemically heterogeneous surfaces, electrowetting could control the surface free-energy landscape of the solid-liquid interface dynamically with the applied voltage. In this work, we study the anisotropic spreading of droplets on striped electrodes (interdigitated electrodes) with voltages applied. The contact angles and contact radii of the contact area observed parallel and perpendicular to the striped electrodes are presented quantitatively. Our research may help the understanding of droplet spreading in heterogeneous electric fields and assist in the applications of electrowetting.