Mesoporous materials with hierarchical structures and well-defined morphologies have attracted a great deal of research interest because of their potential applications in drug delivery, catalysis, separation and sensors. We demonstrated a simple synthetic strategy of mesoporous hollow silica spheres using diffusion-induced phase separation in combination with evaporation-induced self-assembly. To do this, we used PDMS-glass hybrid microfluidic flow focusing device which was able to produce monodisperse aqueous emulsions containing pre-hydrolysed silica sol, triblock copolymer (Pluronic F127) as a structure-directing agent, and water-insoluble polymer such as polymethylmethacrylate. Rapid diffusion of cosolvent (tetrahydrofuran) from emulsion droplets induced phase separation inside the emulsion droplets. Further evaporation of water induced the self-assembly of Pluronic F127 template for sol-gel chemistry. High resolution TEM and BET data confirmed that the shells of the obtained microcapsules have hierarchical meso- and macropore network structures.

Microfluidic synthesis of hollow silica spheres with hierarchical pore networks

243rd National Meeting (2012)

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