Emulsion is a disperse system with two immiscible liquids, which demonstrates wide applications in diverse industries. Emulsification technology has advanced well with the development of microfluidic process. Compared to conventional methods, the microfluidics-based process can produce controllable droplet size and distribution. The droplet formation or breakup is the result of combined effects resulting from interfacial tension, viscous, and inertial forces as well as the forces generated due to hydrodynamic pressure and external stimuli. In the current study, typical microfluidic systems, including microchannel array, T-shape, flow-focusing, co-flowing, and membrane systems, are reviewed and the corresponding mechanisms, flow regimes, and main parameters are compared and summarized.

乳液是一种具有两种不混溶液体的分散体系，在各种行业中都有广泛的应用。乳化技术随着微流工艺的发展而取得了很好的进步。与传统方法相比，基于微流体的工艺可以产生可控的液滴尺寸和分布。液滴的形成或破裂是界面张力，粘性和惯性力以及由于流体动力压力和外部刺激产生的力综合作用的结果。在当前的研究中，对包括微通道阵列，T形，流动聚焦，同流和膜系统在内的典型微流体系统进行了综述，并对相应的机理，流动方式和主要参数进行了比较和总结。