Fabrication of Diverse Microparticles in a Unified Microfluidic Configuration

Flow-focusing microfluidic devices have been widely used for generating compound droplets. However, most devices are disposable and difficult to recycle, and key geometrical parameters cannot be changed after fabrication. This paper presents a reusable and adjustable microfluidic device composed of glass capillaries and polydimethylsiloxane. The main components of the device can be freely assembled and disassembled, illustrating the reproducibility and scalability of the device. The channel wall is composed of glass or polydimethylsiloxane, allowing for different wetting conditions. The experiments show that combining capillaries with straight, stepped, and tapered shapes can change the flow field at the channel junction. Thus, compound microdroplets with core-shell, Janus, and ternary morphologies can be generated for the same combination of liquids. The droplets are used to prepare microparticles of different shapes. With the wide selection of off-the-shelf capillaries, this microfluidic configuration can be used for rapid prototyping, and mass production of the devices can allow for high-throughput generation of droplets or particles in parallel.