Preparation of amorphous metal-oxide-core polymer-shell nanoparticles via a microemulsion-based sol-gel approach

A general route toward surface-functionalized amorphous metal oxide nanoparticles via a sol-gel approach is presented. Modified metal alkoxides were obtained by the substitution of alkoxide groups against functionalized pentane-2,4-dione derivatives, which had potential initiating sites for atom transfer radical polymerization (ATEP). Surface-modified amorphous metal oxide nanoparticles of titanium, zirconium, tantalum, yttrium, and vanadium were synthesized using these novel precursors in a microemulsion-based sol-gel process. Particles with diameters below 200 nm were prepared, and the resulting surface-functionalized colloids were used as macroinitiators in ATRP reactions. The combination of the two well controllable processes, i.e., microemulsions for the formation of the inorganic core and ATRP for the polymer shell, allows for the good control over the composition and morphology of these core-shell systems.