Droplet jumping by electrowetting and its application to the three-dimensional digital microfluidics

We introduce droplet jumping by electrowetting (DJE), which stretches droplets to store energy for jumping by electrowetting. The capillarity-driven droplet jumping is effective to overcome the energy barrier, where the threshold for jumping is less than 100 V. We studied the detailed jumping mechanisms with regard to the jumping height and the energy conversion and demonstrated the transport of sessile droplets to upper surfaces under diverse electrode configurations. While the droplet jumping on the superhydrophobic surface is the primary focus of our research, DJE is also found to be possible on conventional Teflon surfaces, envisioning the three-dimensional droplet-based digital microfluidics. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3688487]