抄録
A new concept of electrostatic droplet actuation based on field-induced deformation of the droplet is presented in this paper. The device consists of a diagonal fishbone-shaped electrode array with a hydrophobic coating. When energized with an AC voltage, a droplet dispensed on the electrode undergoes a periodical motion of flattening and restoring the spherical shape, and because of the geometrical asymmetry of the electrodes, its center of mass is shifted bit by bit in each cycle. The actuation speed as high as 2.4cm/s is achieved for a 1μL-droplet on a 240μm-pitch electrode array with 50Hz, 50 Vrms excitation. Droplet sorting and mixing are also demonstrated by bifurcating and merging electrode arrays. The method only requires a pair of planar electrodes that can be fabricated by a single-mask process, and a single-phase power supply, leading to a simple and low-cost droplet-based micro-chemical system.
