Observations of different oscillation modes and control of droplet sequence in alternating droplet generation

Abstract

Controlling the sequence of microdroplet generation is useful for quantitative manipulation of multiple fluids, but little understanding is available for how the sequence can be determined based upon the geometry of a microchannel and the fluid properties. In this work, we study the design of a double Tjunction microchannel, and observe that there are three modes of oscillations of the droplet generation: i) one by one alternate generation, ii) synchronization, and iii) fluctuations. We also report that if the fluids from the two branches have asymmetric properties (e.g. viscosity), we can change the ratios of the droplets in sequence.