Characterization
FTIR absorption spectra of the synthesized sols, coatings, and films were obtained using a Nicolet 550 spectrometer. The synthesized ZrO2 sol was dropped onto a KBr disk and dried in vacuum. For the cured sample, the coating sol was dropped onto a KBr disk, pre-baked at 80C, then UV-cured, and post-baked at 100C. For all scans, the spectra were collected over the wavenumber range of 400–4000 cm1 with a resolution of 4 cm1. Solid-state 29Si-NMR spectra of the cured coatings were recorded on a Bruker DSX400 WB spectrometer at 79.49 MHz. The chemical shifts were expressed in ppm with respect to tetramethylsilane. The size of ZrO2 particles suspended in the sol was determined by dynamic light scattering (DLS), using a Zetasizer (Malvern, DTS 3000HS) at 25C at the concentration of 0.5 wt%.