Controllable microdroplet splitting via additional lateral flow and its application in rapid synthesis of multi-scale microspheres

In this paper, we demonstrate that controllable microdroplet splitting could be obtained via additional lateral flow with simplicity and high controllability. The volume ratio of the two splitting products can be flexibly regulated by adjusting the flow rate ratio between the main and additional lateral flows. The splitting phenomena under different main flow rates were investigated. A volume ratio up to 200 : 1 of the two daughter droplets under a relatively higher main flow rate was experimentally achieved based on our approach. In this case, we have successfully achieved uniform daughter droplets with a smallest diameter of similar to 19.5 +/- 1.6 mu m. With such a design, we have synthesized uniform PEGDA hydrogel microspheres with diameters ranging from similar to 30 mu m to over hundred of micrometers simultaneously.