Effect of particle coverage on morphology of SiO2-covered polymer microspheres by Pickering emulsion polymerization

Pickering emulsion polymerization is of particular interest as a simple one-step method to prepare inorganic-covered microspheres. In this article, droplets with different particle coverages of <100%, ≈100% and 100% were prepared by variety of particle amounts, and subsequently, were employed as templates to fabricate hybrid microspheres. Especially, effect of particle coverage on nuclei mechanism and morphology of products was investigated. The results showed that particle-formed film with high coverage suppressed the transport of monomers and radicals across the film, and subsequently, inhabited the polymerization in the continuous phase. Also the results indicated that this inhibiting effect was a crucial factor to the morphology of products. By increasing SiO2 amount to prepare emulsion droplets with high coverage and/or employing inhibitor in continuous phase, dispersive microspheres can be prepared.