UV-curable zirconia (ZrO(2)) nanoparticle coatings, prepared by dispersing highly-crystal line zirconia nanoparticles (4 nm) in tetrahydrofuran with the aid of 3-glycidoxypropyltrimethoxysilane (GPTMS) and following addition of a cationic photoinitiator, were cast on silicon wafers (or glass substrates) by dip-coating or spin-coating and photopolymerized to get transparent ZrO(2) nanoparticle films. Ellipsometrical characterization indicates that the refractive index of the film changes from 1.63 to 1.77 at wavelength of 632 nm when the molar ratio of GPTMS-to-ZrO(2) decreases from 0.30 to 0.15. Nano-indentation tests show that the films exhibit robust mechanical performance though they are not heat-treated. (C) 2009 Elsevier B.V. All rights reserved.