New Insights Into Generating Microfluidic Monodisperse Drops

Abstract

We report a new method for determining monodispersity in the microfluidic generation of water-in-oil single emulsions. The spacing between two consecutive emulsions during their generation is used to identify monodisperse and polydisperse regimes, with monodispersity having a size dispersion of < 9%. A theoretical model accurately predicting our experimental findings for a variety of glass capillary microfluidic devices is also presented. Moreover, a phase diagram of drop diameter as a function of inner and outer fluid flow rates indicates optimal flow parameters for the production of monodisperse drops. Our findings emphasize the robustness of using droplet spacing as the parameter in determining monodispersity, despite geometric differences in microfluidic devices.