Polymer-inorganic hybrid nanoparticles of various morphologies via polymerization-induced self assembly and sol-gel chemistry

The preparation of polymer-silica hybrid nanoparticles of various morphologies is reported. As a first step, polymer nanoparticles were synthesized using an alkoxysilane-functional methacrylic macroRAFT agent. Two different alkoxysilane-containing monomers, 3-(trimethoxysilyl) propyl methacrylate and 3-(triisopropoxysilyl)propyl methacrylate, were used to prepare the solvophilic block for the subsequent polymerization-induced self assembly (PISA) of benzyl methacrylate in ethanol. Various particle morphologies, such as vesicles, spheres and rods could be formed. The primary factor governing nanoparticle shape was the nature of the macroRAFT agent, with the bulkier triisopropoxysilyl group yielding spherical structures; the smaller trimethoxysilyl group allowed for morphological transitions to occur as the length of the solvophobic block was increased. In many cases, the resultant nanoparticle dispersion was highly monodisperse. The influence of RAFT agent type was also studied. The presence of reactive alkoxysilane groups at the particle surface enabled a silica shell to be grown from the surface via condensation of tetraethylorthosilicate (TEOS) in a controlled fashion, resulting in the simple preparation of hybrid nanoparticles.