Fabrication of polymer microspheres using titania as a photocatalyst and pickering stabilizer.

Facile photocatalytic emulsion polymerization was developed to fabricate polystyrene (PS) microspheres using a transparent anatase titania hydrosol both as a photocatalyst and stabilizer. Under the appropriate conditions, PS microspheres with a well-defined particle size distribution can be easily produced from 100 to 830 nm. The effects of cross-linking agent ethylene glycol dimethacrylate (EGDMA) and coupling agent acrylic acid (AA) on the particle size and the size distribution of PS microspheres were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and other characterization means. It is proven that EGDMA and AA play importance roles in the morphology of microspheres. In addition, AA bonds a large number of titania nanoparticles on the surface of PS microspheres because its carboxyl group forms inorganic armored polymer microspheres. This interfacial interaction between titania nanoparticles and PS chains causes the elevated glass-transition temperature of microspheres.