Manufacture of SiO2 microparticles using a mechanically machined and assembled microfluidic device

SiO2 microparticles were manufactured using a mechanically assembled microfluidic device with mechanically machined channels. The principle is that an oil phase SiO2 solution with some photo-initiator is fed into a cross-junction and sheared by an aqueous phase to form monodispersed oil-in-water emulsions. The emulsions are then cured with ultraviolet light and dried to form microparticles. In this work, two plate materials, namely polymethyl methacrylate (PMMA) and quartz glass, were used in the configuration. With the PMMA plates, the microchannels at the cross-junction were U-shaped and 40 μm wide and 40 μm deep (Layout_PMMA); with the quartz glass plates, they were V-shaped and 24 μm wide and 12 μm deep (Layout_quartz-glass). The experimental results show the feasibility of this mechanically machined and assembled device. SiO2 microparticles 50 μm in diameter can be produced with Layout_PMMA; microparticles with a finer size of 5 μm can be produced with Layout_quartz-glass, which is attributed to the finer channel gauge.