Fabrication of ceramic microparticles and capsules via microfluidic processing of a preceramic polymer

A robust technique to fabricate monodispersed ceramic capsules and porous particles from double emulsion drops composed of silsesquioxane preceramic polymer has been developed. A microcapillary microfluidic device was used to generate the monodispersed drops in a single-step process, at rates of up to 2000 drops/sec, depending on the arrangement of the glass capillaries and the control of fluid flows. Once the drops were generated, the silsesquioxane was crosslinked in solution and the crosslinked particles were dried and pyrolyzed in inert atmosphere to form oxycarbide glass particles or capsules. Particles and capsules with diameters ranging from 30 μm to 180 μm, shell (optional) thicknesses ranging from 10 μm to 50 μm and pore (optional) diameters ranging from 1 μm to 10 μm were easily prepared by changing fluid flow rates, device dimensions and fluid composition. Four types of products: solid particle, porous particle, solid capsule and porous capsule were obtained. This technique can be extended to other preceramic polymers and can be used to generate unique core-shell multimaterial particles. Products could be used in either the polymeric state or ceramic state, depending on the applications