Sol-gel synthesis of methyl modified optical silica coatings and gels from DDS and TEOS

Methyl modified silica coatings and gels were prepared from dimethyldiethoxysilane and tetraethylorthosilicate via sol-gel processing and spin-coating. The as-synthesized coatings showed not only anti-reflectivity but also hydrophobicity and high laser damage thresholds compared to pure silica coatings without methyl modification. The existence of methyl groups in the framework was demonstrated by IR and NMR spectroscopy. The microstructure of the xerogels obtained were also characterized and will be discussed.