Morphology design and control of polymer particles by regulating the droplet flowing mode in microfluidic chips
In this work, a new strategy for morphology design and control of polymer particles was developed by regulating the droplet flowing mode in microfluidic chips. Firstly, a simple droplet microfluidic chip was manufactured successfully with the help of three dimensional (3D) printing, which was used to control the morphology of polymer particles. According to their diameter, droplets adopted two types of flowing modes: confining mode and rolling mode. Rod-like droplets were formed in confining mode, while ellipsoid droplets were formed in rolling mode. After solidification of droplets, polymer particles with different morphologies could be obtained. Factors such as velocity, viscosity, and interfacial tension that could affect the flowing mode were studied systematically. Based on this strategy, the aspect ratio of rod-like and ellipsoid polymer particles could be changed simply and more hierarchical morphologies such as hollow-sphere particles can be easily prepared.