TiO_2-双亲共聚物复合纳米粒子的合成与紫外光敏特性

Synthesis and UV Photosensitive Properties of TiO_2-Amphiphilic Copolymer Composite Nanoparticles

用偶联剂乙烯基三乙氧基硅烷改性纳米粒子TiO2,应用超声技术将TiO2纳米粒子分散在甲醇介质中,然后用苯乙烯(ST)原位聚合包封,再用丙烯酰胺或乙烯基吡咯烷酮(VP)共聚,两步原位分散聚合得到了有机聚合物为壳、TiO2为核的有机/无机复合粒子.用红外光谱、紫外-可见光谱、透射电子显微镜等检测手段进行表征.结果显示:由于双亲共聚物对TiO2纳米粒子的敏化作用,紫外-可见光谱图上两种纳米复合粒子的最大吸收峰均有明显红移,并且吸收光谱的范围扩大了,其中尤以TiO2/(PST-co-PVP)为甚.意味着光敏化活性的提高,特别是在可见光谱的范围内.这种情形对宽带隙半导体材料如TiO2纳米粒子的光催化特性是有利的,表明这类材料的应用空间得到了拓展.

The nanometer titanium dioxide particles were modified with the coupling agent vinyltriethoxysilane, dispersed in the medium of methanol applying the ultrasonic technique and encapsulated by in situ dispersion copolymerization with styrene （ST） and then with acrylamide or vinylpyrrolidone （VP）. Titanium dioxide inorganic core and polymer shell composite nanoparticles were successfully prepared by two-step in situ dispersion copolymerizafion. The spectra and micromorphology of two composite nanoparticles were characterized by Fourier transform IR spectroscopy, ultraviolet-visible spectroscopy measurement and transmission electron microscopy. The results show that with the photoactivation formed, which derived from coordination bond between core of TiO2 nanoparticles and shell of amphiphilic copolymers that contain a lot of amide structure, the maximum absorption of both kind of composite nanoparticles are red shifted and the absorption spectra extent of two composite nanoparticles are broadened in the UV-Vis spectra figures, especially TiO2/（PST-co-PVP）. This means their photosensitization and photoactivation are enhanced especially in visible light region. It is advantageous for photocatalytic properties of some wide bandgap semiconductor materials such as titanium dioxide nanoparticles, and indicates that the applied domain of this kind of material is enlarged.