Microfluidic synthesis and post processing of non-spherical polymeric microparticles

Monodisperse spherical and non-spherical particles as well as their suspensions have diverse applications in optoelectronics, photonics, abrasives, catalysis, drug delivery, and field responsive rheological fluids. The synthesis of highly monodisperse particles with tunable functionalities has been a great challenge. Microfluidics technology, however, presents an attractive approach to synthesizing monodisperse non-spherical particles with tunable functionalities for application breakthroughs. The microfluidics method, described in a previous study, uses a UV-curable prepolymer with an appropriate photo-initiator. The prepolymer solution passes through a microfluidic channel positioned on a microscope stage, and a microscope objective focuses UV light that is launched into the microfluidic channel. A photo mask patterned with transparent geometric features that define the shape of the particles masks the UV light to synthesize micron sized organic particles. Typically, particles synthesized using this method remain suspended. However, this study describes post-processing methods that allow the recovery of high fidelity, solvent-free particles. Particles in cubic, tetragonal and cylindrical shapes as well as those in pentagonal, hexagonal and triangular cross sections with a size range of ~40–130 μm were synthesized and collected. Then, they were characterized using electron microscopy and image processing to demonstrate the efficacy of the post processing techniques described.