Fig. 6.

Scheme of the electrode array suitable for EWOD actuation. The width d of the electrode is less than half of the contact radius r_c of the droplet (indicated by the blue circle). This ensures that the droplet overlaps with at least three electrodes. Applying a voltage difference on two adjacent electrodes lowers the surface energy in the overlap region (indicated by the red box). Thus, droplet movement across the electrode lines (red arrow) can be achieved. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)