Study On Silicon Oxygen Polymer Electrospun Fiber Prepared By Sol-gel/Electrospinning Methods

The sol-gel method is a promising technique for obtaining pure materials by hydrolysis and condensation of metal alkoxide under acid or alkali catalyzed condition. Electrospinning is a fiber spinning technique to prepare polymer fibers sized in diameter ranging from nanometer to micrometer. Si-O-Si polymer superfine fibers were prepared by sol-gel and electrospinning methods using tetraethyl orthosilicate (TEOS) as a starting material. These materials will display good application future in compounds, membrane materials, reagent or medicine carriers and so on.Firstly, the silica sol was prepared by a sol-gel method using TEOS as a starting material. Effects of acetic acid, water, and solvents on the spinnability and morphologies of electrospun fibers were investigated. The morphologies of fibers were observed by SEM. When the molar ratio of H₂O/TEOS was 1², electrospun fibers were smooth and continual. While the ratio was up to 4, circular pellets were gained. When the molar ratio of HC1/TEOS was 0.01 ⁰.1, fibers became mutual cementation, and formed intercross network structure with increase of HCl content. Using THF, acetone or ethyl alcohol as solvent, the sols were spinnalbe. With THF or acetone solvent, the electrospun fibers had numerous beads, but with ethyl alcohol as solvent, the fibers were continual and long without any beads.Secondly, silica fibers sized 300⁵00nm in diameters were prepared using electrospinning methods which are flexible and foldable. After dried at room temperature or calcined at 1200℃, the fibers were further characterized by SEM, XRD, FTIR, and TGA respectively. The results show that the silica glass fibers are continuous and generally uniform. Moreover, the fibers with few unhydrolyzed alkoxyl(OC₂H₅) groups could change into inorganic silicon dioxide (SiO₂) in low temperature. After calcined at 1200℃, the amorphous silica fibers were changed into continuous microcrystalline silica fibers.Finally, PDMS/SiO₂ hybrid fibers were prepared by sol-gel and electrospinning methods. The morphologies, components and thermal properties ofthe fibers were characterized by SEM, FTIR, TG respectively. The results indicated that the hydroxyl groups of polydimethylsiloxane (PDMS) and TEOS could be condensed. The hybrid materials had excellent stability at high temperature and the fibers diameter increased with the increase of PDMS content.