Preparation and properties of cross-linked zirconia nanoparticle films on polycarbonate

Highly-crystalline zirconia (ZrO2) nanoparticle was functionalized with 3-(N-aminoethyl) aminopropyltrimethoxysilane (AAPTMS) and dispersed in water at primary particle size level under basic condition (pH 13–14). The aqueous ZrO2 nanoparticle dispersion was cast on a polycarbonate substrate with 1,4-butanediol digylcidyl ether as a cross-linker. Nanoparticle films with as high as 81 wt.% of ZrO2 were obtained through heating the cast dispersion at 120 °C, which are highly transparent. The refractive index ranges from 1.70 to 1.77 at wavelength of 632 nm with the decrease of the amount of AAPTMS attached to ZrO2 nanoparticles. Nanoindentation tests show that the hardness of the film reaches 1.7 GPa. In addition, both punched tape abrasion and nanoscratch tests reveal that the films exhibit prominent scratch resistant performance.