Refractive Index Engineering of Polymer Nanocomposites Prepared by End-grafted Polymer Chains onto Inorganic Nanoparticles

Transparent polymer nanocomposites with high refractive index were prepared by grafting polymer chains onto TiO 2 nanoparticles. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to prepare poly(methyl methacrylate) (PMMA) polymer brushes grafted from TiO 2 nanoparticles. The refractive index of the hybrid material increased from 1.49 for neat PMMA to 1.6 by increasing the loading of TiO 2 to 40 weight percent. UV-vis spectra showed that grafted particles had a transparency of more than 90% in the visible light range. The hybrid particles can be processed into transparent, high refractive index coatings and self-standing films. The grafted TiO 2 nanoparticles can also be easily dispersed into a polymer matrix forming thick, robust transparent polymer nanocomposites.