Preparation of nanoporous silica using copolymer template

Silica solids with different nanoscaled pore diameters were formed from tertraethoxysiliane (TEOS) and copolymer gel of hydroxyl ethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) where the latter worked as the cross-linker. The effects of molar ratio [HEMA]/[EGDMA] of copolymers on the porous structure of silica formed in the template gel were discussed. The properties and structure of gel and porous silica were characterized by Fourier transform infrared spectrometer (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results indicated that the pore diameter of silica could be varied by the [HEMA]/[EGDMA] molar ratio which directly affects the templated structure of copolymer gel. The larger pore diameter was obtained with the increased molar ratio, which corresponds to the decrease in the cross-link density. FT-IR and TGA suggested that the silica moiety is bonded to the network of the copolymer gel due to the gel/silica affinity based on the hydrogen bonding.