Abstract
This paper presents an electrokinetic emulsification scheme that is capable of producing subfemtoliter droplets on demand. Maxwell stress is employed and droplets are produced via tip streaming process. In the prototype demonstration, PDMS microfluidic chips with embedded solid electrodes and diaphragm valves are utilized to control the formation of droplets. By applying a voltage ramp (0 to 400 V in 0.05 seconds) across a distance of 6 mm, droplets of diameters less than 1 ?m are produced. The higher the voltage ramp rate, the smaller the resulting droplet volume. As such, extremely-small droplets can be readily produced on demand.