Abstract
This paper presents a novel droplet formation scheme that can electrically generate sub-femtoliter droplets in a desired manner. Typical pressure-driven flow-focusing scheme is enhanced by an AC electric field, which deforms the fluidic interface and causes droplet breakup around the tip. In the prototype demonstration, PDMS microfluidic devices with embedded alloy electrodes are fabricated and characterized. Alternating electric fields with frequencies up to 1 kHz and magnitudes less than 1 V/μm are utilized in the trials. It is demonstrated that the emulsification process is controlled by the applied electric field, and extremely-small droplets with volumes less than 1 femtoliter can be readily generated and collected.