Droplet jumping by resonant AC electrowetting envisioning three-dimensional digital microfluidics*

We introduce droplet jumping by resonant AC electrowetting (DJ-RACE) to transport droplets to vertical direction, envisioning three-dimensional digital microfluidics. Inphase oscillatory actuation by resonant AC electrowetting allows droplets to store sufficient energy for jumping on their stretched surfaces by conventional electrowetting methods. The detailed jumping mechanism is explained in comparison to experimental results, and the actual droplet transport from the superhydrophobic bottom surface to higher level surfaces is demonstrated by several electrode configurations and actuation methods.