PEG和PVP改性溶胶-凝胶二氧化硅减反膜的对比

聚乙二醇(PEG)和聚乙烯吡咯烷酮(PVP)对溶胶-凝胶二氧化硅减反膜的结构和激光损伤阈值(LIDT)有不同的影响.动态光散射、透射电镜(TEM)以及小角X射线散射实验表明:PEG能够促进二氧化硅颗粒的生长并增加团簇生长的一致性.然而,在PVP改性的溶胶中,Si―OH与PVP之间氢键作用制约了二氧化硅颗粒的生长.此外,多重分形谱(MFS)分析表明,PEG可以提高氧化硅薄膜的均匀性,PVP却降低了薄膜的均匀性,因此,PEG改性的氧化硅薄膜的抗激光损伤性能增强,而PVP改性的氧化硅薄膜的抗激光损伤性能被削弱.固体29Si魔角旋转核磁共振(MASNMR)结果表明,PEG能够提高Si―O四面体缩聚程度并改善薄膜的表面分形结构,PVP则相反,导致了PEG改性的氧化硅薄膜与PVP改性的氧化硅薄膜具有不同的抗激光损伤性能.

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.29 Si 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.