Epoxy‐based hybrids using TiO 2 nanoparticles prepared via a non‐hydrolytic sol–gel route

TiO 2 nanoparticles with an average diameter of less than 10 nm were prepared via a non‐hydrolytic sol–gel route in a TiCl 4 –diisopropyl ether–CH 2 Cl 2 system. After modification with n ‐octylphosphonic acid (OPA) to increase their organophilic character, the TiO 2 nanoparticles were used for preparation of TiO 2 /epoxy hybrid films. Characterization by FT‐IR, solid‐state 13 C cross‐polarization/magic angle spinning (CP/MAS) and 31 P MAS NMR techniques showed the preservation of the n ‐octyl groups and the presence of TiOP bonds on the surface of TiO 2 nanoparticles. Hybrid films with various TiO 2 contents were prepared via a wet process and casting using CH 2 Cl 2 as a solvent. The resulting films were highly transparent. The refractive indices of TiO 2 /epoxy hybrid films at 633 nm increased monotonously from 1.51 for the pure polymer to 1.66 for the hybrid containing 62.4 mass% of TiO 2 nanoparticles. Copyright © 2013 John Wiley & Sons, Ltd.