서강대학교

초록/요약

In this study, the synthesis and the results for the characterization of new water-soluble anatase titanium dioxide nanoparticles stabilized by poly(ethylene oxide) (PEO)-based polymers are reported. First, PEO-folate conjugates was synthesized by the reaction of ω-anhydride-functionalized poly(ethylene oxide) and folic acid. Poly(ethylene oxide) (PEO) was obtained from anionic ring-opening polymerization of ethylene oxide in the mixture of benzene and dimethylsulfoxide using n-butyllithium with t-butoxide at 35 oC. The resulting PEO exhibited a living nature. Poly(ethylene oxide -b- maleic acid) was synthesized by deimidation of poly(ethylene oxide -b- N-phenylmaleimide) which was prepared by block copolymerization of N-phenylmaleimide using polymeric alkoxide via sequential monomer addition method. Those polymers were found to be effective to stabilize nano-sized transition metals. Using PEO-based stabilizers, nano-sized titanium dioxide was prepared by a conventional process such as in aqueous media or organic solvents. The resulting nanoparticles exhibited no anatase crystalline structure at room temperature. After calcination, they showed anatase structure which affected a catalytic efficacy as a photocatalyst. Finally, new water-soluble titanium dioxide nanoparticles using poly(ethylene oxide -b- maleic acid) and PEO-folate conjugate as stabilizers exhibiting anatase crystalline structures at room temperature were successfully synthesized in alcohol at 70 oC. The particle sizes were able to be controlled in the range of 1~8nm. The resulting products were characterized by the combination of 1H-NMR spectroscopic, transmission electron microscopic, electron, and X-ray diffraction, Raman spectroscopy, Thermogravimetry Analyzer, UV/Visible spectroscopic analysis. And the photocatalytic activity of our water-soluble titanium dioxide nanoparticles were evaluated decomposition of the methylene solution as increasing irradiation time about UV light. We confirmed photocatalytic activity as a photocatalyst by estimation method of UV absorbance.