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题名	TiO_2基薄膜的Sol-Gel制备、表征及润湿性能研究
作者	陈静
学位类别	硕士
答辩日期	2000
授予单位	中国科学院上海光学精密机械研究所
导师	侯立松
关键词	TiO_2薄膜 SiO_2-TiO_2薄膜 F搀杂 润湿性能
中文摘要	TiO_2基薄膜的润湿性能在其诸多应用中有重要作用，关于这方面的研究却极少进行。在本论文工作中，成功制备了均质、透明的TiO_2系列薄膜，运用XRD、XPS、AFM等现代分析手段对薄膜的性能进行表征，并着重对薄膜的润湿性能进行了实验研究和机理分析。一、TiO_2基薄膜的制备工艺和性能表征通过sol-gel过程制备了高质量的TiO_2、SiO_2-TiO_2薄膜，并首次成功制备了掺氟的SiO_2-TiO_2薄膜。在这部分的工作中，我们探讨了搀杂剂对TiO_2基薄膜的光学、晶体学和表面形貌的影响。在掺氟的SiO_2-TiO_2薄膜的制备中，分别以有机氟试剂和HF为氟搀杂剂，XPS研究发现有机氟试剂具有更好的搀杂效果。搀杂氟进一步提高了TiO_2薄膜的锐钛矿析出温度，SAXS结果表明凝胶颗粒为平滑界面的致密结构。二、TiO_2基薄膜润湿性能的自发变化我们发现薄膜开始具有接近0 ℃的接触角，在放置达一定时间时，接触角开始变大，并最终达到一个饱和值θ，即发现了表面润湿性能变差的潜伏期(Incubation Period)和饱和(Saturation)现象。这个变化在很大程度上受H_2O影响，潮湿环境下的变化较快。络合剂对接触角开始变大时间和变大速度的影响不相同：DEA加快了变化；而acac没有产生影响；但DEA和acac对θ起始值和饱和值均不产生影响。搀杂齐SiO_2和氟对薄膜接触角变化产生相反的影响，分别起抑制和促进作用；同时，SiO_2还对θ的大小产生较大影响：随SiO_2搀杂浓度的增大，θ变小。三、TiO_2基薄膜润湿性能的控制恢复在接触角达饱和值后，紫外光辐照可使纯TiO_2薄膜的接触角减小到接近0°；搀杂SiO_2和氟均会减弱紫外辐射对薄膜润湿性能的影响。这表明，可以通过适当添加SiO_2、氟以及用紫外光辐照的方法控制恢复TiO_2基薄的膜润湿性能。四、TiO_2基薄膜润湿性能可逆的变化的机理分析对TiO_2材料表面的润湿性能的变化还进行了机理分析。薄膜表面接触角增大是因为有机物吸附和表面氧空位的消失引场的。搀杂氟减少了表面氧空位；而搀杂SiO_2抑制有机物的吸附，减弱氧空位对周围区域的影响；氟和SiO_2之间又会发生相互作用，因而减弱了彼些对薄膜润湿性能的影响。从两方面解释了紫外光辐照增强了薄膜表面的润湿性能：(1)紫外辐照导致TiO_2光催化，从而使薄膜表面吸附的有机杂质被氧化分解；(2)紫外辐照使表面氧空位重新产生，从而提高表面的润湿性能。
英文摘要	Surface wettability of TiO_2-based films play a important role in their wide application, but there were little work have been done on it. In the present work, transparent and homogeneous TiO_2-based films were fabricated by sol-gel process, and characterize by modern analytical methods such as XRD、XPS、AFM. A systematic experimental study and mechanism analusis were carried out on the wettability of the films in particular. (1) Preparation and characterization of TiO_2-based films Pure TO_2 films, SiO_2-TiO_2 films and F-doped SiO_2-TiO_2 films were fabricated, the F-doped SiO_2-TiO_2 high quality films have been successfully prepared by the sol-gel process for the first time. The effects of dopant on the optical properties、surface morphology and wettability of the films were explored, too. In the preparation of F-doped SiO_2-TiO_2 films, organic Fluoride and HF are used as the dopants, XPS results showed that the concentration of Fluorine ion in the film is higher when organic Fluoride is used. SAXS results revealed that the gel particles of the F-doped SiO_2-TiO_2 have dense structure with smooth surface. (2) Spontaneous increase in water contact angle of TiO_2-based film surface It was found that the as-deposited films had the contact angles(θ) to water of near 0°. After some time of storage(incubation period), the contact angles increase till it reach the saturated value(θ_s) about 72°. Water adsorption was found to be one of the factors which cause the increase in the contact angle. The chelate agents used in our experiments have different effect on the increase of θ, and DEA is an accelerator. But all the chelate agents have no effect on θ_2. SiO_2 and F have contrary effect on the increase of the contact angle of TiO_2-based films: SiO_2 has the effect of inhibition, and F has the effect of acceleration. SiO_2 can also decrease the value of θ_s. (3) Controllable resumption of the hydrophilicity of TiO_2-based films After θ reaches the saturated value, appropriate UV light irradiation could make the water contact angle of the films decrease down to a minimum near 0°. Both SiO_2 and F have negative effect on the decrease of θ. When the concentration of doped SiO_2 is more than 5%, UV light irradiation couldn't make the water contact angle of the films decrease down to <5°.This makes it possible to realize controllable resumption of the hydrophilicity of sol-gel-derived TiO_2-based films by the combination of introducing appropriate additives and UV-light irradiation. (4) Mechanism analysis of the reversible change in the wettability of TiO_2-based films The adsorption of organic contaminant and the elimination of oxygen vacancy on the film surface are proposed to cause the increase of the water contact angle of TiO_2-based films. SiO_2 can inhibit the adsorption of organic contaminant and weaken the effect of Ti~(3+) sites to their surrounding sites. Doping of F ions can decrease the concentration of oxygen vacancy. But when SiO_2 and F are doped into TiO_2 films together, there would be a reaction between SiO_2 and F, and their effects are weakened. Under UV-light irradiation, the organic contaminant are oxidized and decomposed into CO_2 and H_2O, and oxygen vacancies are created, resulting in the increase in the wettability.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/16486]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	陈静. TiO_2基薄膜的Sol-Gel制备、表征及润湿性能研究[D]. 中国科学院上海光学精密机械研究所. 2000.

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