Synthesis of hybrid TiO2 nanoparticles with well-defined poly(methyl methacrylate) and poly(tert-butyldimethylsilyl methacrylate) via the RAFT process

Surface of titania nanoparticles (TiO2) was modified by a coupling agent as 3-(trimethoxysilyl)propyl methacrylate (MPS) to form TiO2-MPS polymerizable particles. Methyl methacrylate (MMA) and tert-butyldimethylsilyl methacrylate (MASi) were radically polymerized through the immobilized vinyl bond on the surface in the presence of the reversible addition-fragmentation chain transfer (RAFT) agent 2-cyanoprop-2-yl dithiobenzoate using 2,2′-azobisisobutylnitrile (AIBN) as an initiator. FTIR spectroscopy confirmed the presence of the coupling molecule and the methacrylate groups on the surface. Thermogravimetric analysis and elemental analysis revealed a surface coverage of the coupling molecule of 2.0 wt%. TGA measurements showed that grafted PMMA and PMASi were accounted for 10% and 4.8% of the particle mass, respectively. 1H NMR and SEC were used to verify the livingness of the polymerization. Transmission electron microscopy (TEM) was used to study the morphology of the particles before and after the surface grafting.