Monodisperse emulsion generation via drop break off in a coflowing stream

We describe an experimental technique for the production of highly monodisp erse emulsions (with minimum achievable polydispersities <3%). The phase to be dispersed is introduced into a coflowing, surfactant-laden continuous p hase via a tapered capillary. Drops detach from the capillary when the stre amwise forces exceed the force due to interfacial tension. Drop size is a f unction of the capillary tip diameter, the velocity of the continuous phase , the extrusion rate, and the viscosities and interfacial tension of the tw o phases. Emulsions composed of a variety of fluids and with drop sizes ran ging from 2 to 200 mu m have been produced using this technique.