Geometrically Mediated Breakup of Drops in Microfluidic Devices
Howard Stone and coworkers describe two techniques for breaking up droplets in an emulsion using microfluidic devices. The first method makes use of a "T junction," in which a droplet flows down a channel that abruptly branches out into two channels in an orthogonal direction. The second method involves placing an obstacle in the droplet's path. Also notable is the article's analysis of the conditions under which a droplet encountering a T junction will actually break up.
Using T junctions
The process of creating droplets in the first place was previously described by [Steve Quake and coworkers.