Dielectrophoretic manipulation of drops for high-speed microfluidic sorting devices

We demonstrate a high-throughput drop sorter for microfluidic devices that uses dielectrophoretic forces. Microelectrodes underneath a polydimethylsiloxane channel produce forces of more than $10\mathrm{nN}$ on a water drop in an inert oil, resulting in sorting rates greater than $1.6\mathrm{kHz}$ . We investigate the dependence of such forces on drop size and flow. Alternate designs with electrodes on either side of a symmetric channel $Y$ junction provide refined control over droplet selection.