Preparation and optical properties of silica-poly(ethylene oxide) hybrid materials

Abstract

Structural evolution and optical properties of the silica-poly(ethylene oxide) hybrid films prepared from gamma-glycidoxypropyltrimethoxysilane (GPTS) and 1-methylimidazol (MI) are studied. Polymerization of the epoxy groups is achieved by using 1-methylimidazol as a thermal curing agent. In liquid state H-1 & C-13 NMR spectroscopy, it is found that silica condensation mainly occurs without epoxy ring opening. The epoxide polymerization is confirmed by using FT-IR, solid state CP-MAS C-13-NMR, and differential scanning calorimetry (DSC). The hybrid material is densified due to the epoxide polymerization as well as silica condensation with thermal curing. As a result, the thermal curing increases refractive index and extinction coefficient and shifts UV optical absorption edge to longer wavelength.