Synthesis of titania/polymer core-shell hybrid microspheres

Monodisperse titania/polymer core-shell microspheres were prepared by a two-stage reaction with titania as core and poly(ethyleneglycol dimethacrylate) (PEGDMA) as shell, in which the titania cores were synthesized by a sol-gel method and subsequently grafted with 3-trimethoxysilyl methacrylate as the first-stage reaction to incorporate the vinyl groups on the surface of inorganic core. The PEGDMA shell was then encapsulated over the MPS-modified titania core by distillation precipitation polymerization of ethyleneglycol dimethacrylate in neat acetonitrile during the second-stage polymerization via capture of the radicals of EGDMA with the aid of the reactive vinyl groups on the surface of inorganic core without any stabilizer or surfactant. The shell thickness of the core-shell hybrid microspheres was controlled by the feed of EGDMA monomer during the polymerization. The resultant titania particles and core-shell microspheres were studied by transmission electron microscopy, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, and thermogravimetric analysis.