Nanosized Organo-Silica Particles with "Built-In" Surface-Initiated Atom Transfer Radical Polymerization Capability as a Platform for Brush Particle Synthesis.

A facile synthetic method was developed to prepare sub-5 nm organo-silica (oSiO 2 ) nanoparticles through the self-condensation of atom transfer radical polymerization (ATRP)-initiator-containing silica precursors. The obtained oSiO 2 nanoparticles were characterized by a combination of nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), dynamic light scattering (DLS), and small-angle neutron scattering (SANS). The accessibility of the surface-Br initiating sites was evaluated by the polymerization of poly(methyl methacrylate) (PMMA) ligands from the surface of the oSiO 2 nanoparticles using surface-initiated atom transfer radical polymerization (SI-ATRP). The ultrasmall size, tunable composition, and ease of surface modification may render these organo-silica nanoparticle systems with built-in SI-ATRP capability an interesting alternative to conventional silica nanoparticles for functional material design.