"Tips and tricks: Snap-off production of monodisperse droplets"
S Barkley, ER Weeks, and K Dalnoki-Veress, Eur. Phys. J. E 38, 138 (2015)

We introduce a novel technique to produce monodisperse droplets through the snap-off mechanism. The methodology is simple, versatile, and requires no specialized or expensive components. The droplets produced have polydispersity < 1% and can be as small as 2.5 micrometer radius. A convenient feature is that the droplet size is constant over a 100-fold change in flow rate, while at higher flows the droplet size can be continuously adjusted.