Droplet Manipulation using AC Ewod-Actuated Anisotropic Ratchet Conveyor

This paper demonstrates an AC electrowetting-on-dielectric (EWOD) based platform to manipulate water droplets using anisotropic patterning of electrodes, without the need of complex control circuits. Only two electrodes are required to transport the droplet. Different droplet sizes (5~15 μL) have been tested and the droplet transport speed can reach 20 mm/s for 15 μL at 20 Hz external AC frequency. By introducing DC EWOD electrodes, we can perform multiple droplet manipulating functionalities including droplet synchronizing, merging, and mixing, which provides potential applications including active self-cleaning surfaces and lab-on-chip instruments.