Comparision of Silica Anti-Reflective Films Obtained via a Sol-Gel Process in the Presence of PEG or PVP

The different effects of poly(ethylene glycol) (PEG) and poly(vinylpyrrolidone) (PVP) on the structure and laser-induced damage threshold (LIDT) of sol-gel silica anti-reflective films were investigated. The results of dynamic light-scattering, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS) showed that PEG could prompt silica particles to form uniform clusters, whereas in the PVP-modified sol, the growth of silica particles was restricted. This was a result of the strong hydrogen bonds between Si - OH groups and PVP molecules Multi-fractal spectrum (MFS) analysis suggested that PEG improved the uniformity of the silica film but PVP reduced it, therefore the laser-damage resistance of the PEG-modified silica film was enhanced, but that of the PVP-modified silica film was weakened. Si-29 magic-angle spinning nuclear magnetic responance (MAS NMR) showed that PEG improved the condensation of Si - O tetrahedron, but PVP did not. This led to differences between the laser-damage resistances of PEG-modified silica films and PVP-modified silica films.