【作者】 黄伟欣；

【导师】 黄洪；

【作者基本信息】 华南理工大学 ， 化学工程， 2010， 硕士

【摘要】 随着科学技术的不断发展,超亲水性能的薄膜,因其具有高性能而引起了各国学者的极大关注。尽管目前超亲水薄膜的制备方法多种多样,但由于制备工艺复杂的限制,使该薄膜尚未得到普遍应用。本文依据超亲水性能的形成原理,基于具有光催化性能的TiO2薄膜,通过用模板剂法和双络合剂法制备了表面具有孔状结构的超亲水膜。本文以钛酸四丁酯为钛前体,聚乙二醇(PEG)为模板剂,采用溶胶凝胶法制备具有微米和纳米级孔状结构的TiO2薄膜。随着PEG添加量的增加,薄膜孔径逐渐增大,孔穴逐渐加深,比表面积也逐渐增大。当PEG含量少于临界值(0.002 0.0025 M)时,小裂缝在热处理过程会因在锻烧过程中颗粒的聚合使裂缝消失。而当PEG含量高于0.02 M时,PEG会跟TiO2颗粒交联起来逐步形成三维网络结构而抑制TiO2聚合的产生,同时薄膜出现开裂现象。实验结果表明,TiO2多孔薄膜表面粗糙不平,在自然光的条件下跟水接触角小于5°。本文利用乙酰丙酮(acac)和二乙醇胺(DEA)作为络合剂,采用溶胶凝胶技术,以钛酸丁酯为前驱体,在玻璃基片上制备了二氧化钛多孔薄膜。单独以乙酰丙酮(acac)或二乙醇胺(DEA)作为络合剂,制备的涂膜十分致密和平坦,水接触角分别为20°和23°。但以两者复合使用,由于低缩聚物迅速形成,使溶液体系产生二相分离,随着二乙醇胺加入量的增加,两相完全分离所需的时间逐渐减少,在煅烧过程中,溶剂挥发时,放出二氧化碳气体形成了孔状结构,从而使表面具有更大的平均粗糙度。多孔TiO2的涂膜在避光的条件下与水接触角达6.5°。利用Wenzel和Cassie理论对多孔表面超亲水现象进行解释,讨论了两种理论在亲水区域中的相互转换的条件,计算出了多孔TiO2薄膜的临界接触角,分析了多孔TiO2薄膜的超亲水机理。更多还原

【Abstract】 With the development of science and technology, the superhydrophilic surfaces were paid attention to for their high properties. Although a lot of methods were used for preparation of superhydrophilic surfaces, they were not used widely owing to their complicated processes.According to superhydrophilic mechanics, the superhydrophilic porous films based on TiO2 surface with the light catalyst property were prepared using methods of template agents and double complexing agentsThe nanopores and micropores TiO2 films were prepared using tetrabutyl titanate as titanium precursor, polyethylene glycol (PEG) as a templating reagent by sol gel method.With the increasing of the PEG, the pores of film became larger and deeper, and the specific surface area increased also. When the amount of PEG was lower than the critical value 0.002 0.0025 M, the numerous small cracks disappeared on the surface. PEG molecules would not contribute to a complete enlargement of aperture, and the shape of holes would become irregular and fluctuating when the content of PEG was above 0.02 M. The experimental results showed that the surface of TiO2 films was rough and the contact angle with water was lower 5o under the natural light condition.When acac or DEA as the complexing agent, the film was compact and flat, and the contact angle with water was about 200 and 230 respectively.When the acac and DEA were used as complexing agents together, the phase separated for oligomers formation. With the increasing of the PEG, the time of the phase separated decreased. The surface roughness of the films increased for the carbon dioxide produced by the solvent when the films were calcined. The contact angle with water of the TiO2 films was about 6.50 under the no light condition.The superhydrophilic behavior was explained by the Wenzel and Cassie wetting impregnating model. The transition between these two wetting regimes was investigated. The criteria contact angle with water of the porous TiO2 films was got. And the superhydrophilic mechanics of the TiO2 films was also analyzed.更多还原