We explore the physics behind high-throughput devices for the production of monodisperse microdroplets. Microdroplets are used more and more in a wide variety of applications: to conduct chemical reactions in picoliter volumes, as biological screening assays or as templates to produce calibrated microparticles and microcapsules of active ingredients. The accuracy of the screening assays as well as the degree of control over the chemical reactions and the release kinetics of active ingredients critically depend on a very narrow size distribution for the microdroplets. In addition, a very large number of drops is required. Unfortunately, traditional high throughput methods offer limited control over the drop size.
In 2013, the Weitz laboratory at Harvard University introduced a robust device that produces monodisperse drops at a high throughput. This device, called centipede because of its hundreds of parallel channels, allows the use of microdroplets for a much broader range of applications. A single device takes up a volume of 100 mm3 and can produce up to 150mL/h of monodisperse microdroplets: size variations remain below 3%. In this talk we explain the mechanism through which it produces droplets in order to understand how the droplets’ size is related to the device’s design parameters and what the limiting throughput is.
