(469g) Continuous Synthesis of Organic/Inorganic Microparticles Using a Low-Cost Flow-Focusing Microreactor

The expanding capabilities of droplet microfluidic techniques throughout their three decades of use has driven advancement in medical, biological, and chemical research fields. Microfabricated devices offer compact integration of micromixing modules, flow junctions, and patterned heating elements; however, they often demand a significant capital expenditure and require extensive training to design, fabricate, and operate the microreactor. To capitalize on the process intensifications intrinsic to microscale flow systems, the broadening research community stands to benefit from lower-cost, reconfigurable microreactors.

In this work, we present a novel strategy to synthesize organic/inorganic microparticles using a multiphase flow-focusing microreactor and demonstrate their application in heterogeneous catalysis.^1-3 The monodispersed microparticles are produced in a coaxial glass capillary-based 3D flow-focusing microreactor constructed using off-the-shelf components without the use of epoxy. The developed microfluidic platform is equipped with an in-line photocuring module using a collimated high-power UV LED light source. Utilizing the developed microfluidic platform, we continuously synthesize (I) elastomeric microparticles using on-line chemical cross-linking and (II) titania microparticles using in-line photocuring. Next, we utilize the flow-focusing microreactor with a templating approach to produce macroporous elastomeric microparticles with tunable porosity. We also study the addressable microparticle diameter parameter space and attainable flow regimes within the multiphase microfluidic reactor. We use a suite of off-line characterization techniques including scanning electron microscopy, micro-computed tomography, rheometer, and x-ray diffraction to study the structural properties of the produced dense/porous microparticles post-crosslinking.

we believe the new, low-cost microfluidic platform will help encourage researchers in diverse disciplines to incorporate microfluidic techniques into their work. The low-cost nature, in addition, enables the ability to scale up which is an important consideration for the growth of microfluidics.

(1) Bennett, J. A.; Kristof, A. J.; Vasudevan, V.; Genzer, J.; Srogl, J.; Abolhasani, M. Microfluidic synthesis of elastomeric microparticles: A case study in catalysis of palladium-mediated cross-coupling. AIChE Journal 2018, 64, 3188-3197.

(2) Campbell, Z. S.; Parker, M.; Bennett, J. A.; Yusuf, S.; Al-Rashdi, A. K.; Lustik, J.; Li, F.; Abolhasani, M. Continuous Synthesis of Monodisperse Yolk–Shell Titania Microspheres. Chemistry of Materials 2018, 30, 8948-8958.

(3) Bennett, J. A.; Campbell, Z. S.; Abolhasani, M. Continuous synthesis of elastomeric macroporous microbeads. Reaction Chemistry & Engineering 2019, 4, 254-260.