Controllable droplet breakup in microfluidic devices via hydrostatic pressure

摘要

We developed a simple, flexible method for precise control of droplet breakup in a microfluidic chip is to use hydrostatic pressure. By adjusting the pressures on the continuous phase via liquid columns, water droplets were split into two daughter droplets at a T-junction, and the relation between the sizes of daughter droplets and pressures was investigated experimentally and rationalized theoretically using simple physical arguments. We found that droplet break up was stable only over a certain range of pressure with the size ratio of daughter droplet to mother droplet ranging from 0.3 to 0.7 approximately. In a certain physical system, the behaviour of breakup becomes uncontrollable and uncertain over two ranges of pressures, suggesting a chaotic phenomenon existing. In contrast with other techniques for droplet breakup, the simplicity and flexibility of the pressure-controlled method for droplet breakup and sorting will endow the droplet-based microfluidics for a wide range of applications. (C) 2020 Elsevier Ltd. All rights reserved.