The quantitative effect of silica nanoparticles on optical properties of thin solid silica UV-cured films

Abstract

A thin solid silica UV-cured film was prepared by coating the dispersion of commercial silica nanoparticles in a UV-curable acrylate monomer on a glass substrate using a bar coater. The silica UV-curable acrylate resin was stored for 24h in the dark for film formation and then transformed into the thin solid silica UV-cured films upon exposure to UV light at the wavelength of 254nm for 5min at ambient temperature. The amount of silica nanoparticles in the UV-cured films was varied from 1 to 30vol.% and then the optical properties of the coated glass were compared with the bare glass. The result revealed that the total transmittance of all the films is insignificantly different when the amount of silica nanoparticles increases. The total transmittance of all the coated glasses is similar to that of the bare glass indicating the transparency of the film. Although the total transmittance of the films is independent of the amount of particles, the improved diffuse transmittance of the films is obtained as the amount of particles increased. This is due to the enhanced multiple scattering that occurs in the film. The increased amount of silica nanoparticles also leads to the formation of the aggregated particles with a larger size and homogeneous dispersion as evidenced from the FE-SEM images. These indicated that the amount and distribution of the silica nanoparticles strongly affect the improved optical properties of the thin solid silica UV-cured film.