Liquid-Metal Microdroplets Formed Dynamically with Electrical Control of Size and Rate.

Liquid metal co-injected with electrolyte through a microfluidic flow-focusing orifice forms droplets with diameters and production frequencies controlled in real time by voltage. Applying voltage to the liquid metal controls the interfacial tension via a combination of electrochemistry and electrocapillarity. This simple and effective method can instantaneously tune the size of the microdroplets, which has applications in composites, catalysts, and microsystems.