【作者】 张伟；

【导师】 张凤君； 冯威；

【作者基本信息】 吉林大学 ， 环境工程， 2013， 博士

【摘要】 目前，对杂多金属化合物的基础和应用研究引起人们广泛的关注，以杂多金属化合物为基础的功能性复合材料和器件的研究得到了逐步发展，制备杂多金属化合物的功能性复合材料的新方法也不断涌现。其中，薄膜技术允许将不同种类和功能的物质按照某种需要进行复合，必将赋予薄膜材料更新的功能。因此，杂多金属化合物基光致变色复合薄膜的制备与性能研究一直是人们感兴趣并不断探索的研究课题。本论文针对目前国内外杂多金属化合物基可见光光致变色体系研究较少的现状，通过杂多金属化合物与有机高分子或与可见光激发的无机半导体纳米材料复合，构建杂多金属化合物基可见光光致变色纳米复合薄膜体系。研究复合薄膜组成、结构与可见光光致变色性能间的内在关系。提出杂多金属化合物基可见光光致变色纳米复合薄膜体系的可能机制，从而为相关光致变色体系的研究提供理论基础。该系列材料在环境监测与污染治理领域具有潜在的应用前景。1.采用滴膜法利用氢键作用制备了具有可逆光致变色性能的磷钼酸-乙基纤维素复合薄膜，磷钼酸-乙基纤维素复合薄膜具有良好的光致变色性质。通过红外光谱、紫外可见光谱、原子力显微镜、X-射线光电子能谱等测试手段研究了磷钼酸-乙基纤维素复合薄膜复合薄膜的结构、光致变色性质及机理。红外光谱FT-IR和原子力显微镜AFM结果表明磷钼酸-乙基纤维素复合薄膜可见光光照前后在形貌、微结构上存在差异。FT-IR分析结果表明，Keggin结构磷钼酸分子的基本结构在磷钼酸-乙基纤维素复合薄膜中仍然存在。AFM结果表明复合前后以及磷钼酸-乙基纤维素复合薄膜光照前后的表面形貌发生了变化。在可见光光照下磷钼酸-乙基纤维素复合薄膜由无色变为蓝色，紫外可见吸收光谱表明复合膜中发生了电子由乙基纤维素向杂多阴离子的转移，分散在乙基纤维素高分子中的磷钼酸阴离子在可见光光照射下能够被还原，生成杂多蓝。2.采用滴膜法利用氢键作用制备了具有可逆光致变色性能的磷钼酸-聚乙烯吡咯烷酮复合薄膜，磷钼酸-聚乙烯吡咯烷酮复合膜具有良好的光致变色响应性和可逆性。通过红外光谱、紫外可见光谱、原子力显微镜、X-射线光电子能谱等测试手段研究了磷钼酸-聚乙烯吡咯烷酮复合薄膜的结构、光致变色性质及机理。红外光谱FT-IR和原子力显微镜AFM结果表明磷钼酸-聚乙烯吡咯烷酮复合薄膜可见光光照前后在形貌、微结构上存在差异。FT-IR分析结果表明，Keggin结构磷钼酸分子的基本结构在磷钼酸-聚乙烯吡咯烷酮复合薄膜中仍然存在。AFM结果表明复合前后以及磷钼酸-聚乙烯吡咯烷酮复合膜光照前后的表面形貌发生了变化。在可见光光照下磷钼酸-聚乙烯吡咯烷酮复合膜由无色变为蓝色，紫外可见吸收光谱表明复合膜中发生了电子由聚乙烯吡咯烷酮向杂多阴离子的转移，分散在聚乙烯吡咯烷酮高分子中的磷钼酸阴离子在可见光光照射下能够被还原，生成杂多蓝。3.采用溶胶-凝胶法制备了具有可逆光致变色性能的PMoA/SiO₂/ZnFe₂O₄复合薄膜，PMoA分子均匀地分布在PMoA/SiO₂/ZnFe₂O₄复合薄膜中。PMoA/SiO₂/ZnFe₂O₄复合膜具有良好的光致变色响应性和可逆性。通过一系列测试手段研究了复合膜的结构、光致变色性质及机理。结果表明PMoA/SiO₂/ZnFe₂O₄复合薄膜复合前后在形貌、微结构上存在差异。FT-IR分析结果表明，Keggin结构磷钼酸分子的基本结构在复合薄膜中仍然存在，在PMoA与ZnFe₂O₄间形成电荷转移桥。AFM结果表明复合前后以及PMoA/SiO₂/ZnFe₂O₄复合膜光照前后的表面形貌发生了显著变化。在可见光光照下复合膜由无色变为蓝色，杂多酸被还原产生杂多蓝。XPS结果表明ZnFe₂O₄受可见光激发产生光生电子，导致磷钼酸发生光还原反应，生成杂多蓝。体系的光致变色过程是按照光生电子转移机制进行的。4.采用LBL技术制备PMoA/PAM自组装多层结构复合膜，研究复合膜的微结构及其在紫外光和可见光下的光致变色性能及机理。PMoA/PAM LBL膜在制备过程中实现了稳步增长，并具有稳定的结构。PMoA以球形结构均匀地分散在高分子体系中。在可见光和紫外光照射下复合膜均由无色变为蓝色，杂多酸分子被还原成杂多蓝，在该过程中复合膜展现了良好的光致变色性能。其光致变色机理可以解释为，PMoA/PAM LBL膜经光照激发后，电荷转移桥上的酰胺基的质子氢通过该桥转移给多酸的氧原子，导致多酸八面体结构的O→Mo配体金属电荷转移键发生还原。更多还原

【Abstract】 So far, basic and applied researches on polyoxometallates have attracted widespreadattention; studies on polyoxometallate-oriented functional composites and components havebeen developed increasingly; and new preparation methods of polyoxometallate functionalcomposites are also constantly emerging. Thin film technology, allowing materials ofdifferent types and functions to be synthesized as required, will certainly give thin-filmmaterials newer features. Hence, it is always an interesting and exploring research subject forthe preparation and performance study of heteropolyometalates photochromic compositefilm.For all we know, there is less research about the visible-light photochromic system basedon heteropolyometalates （HPOM） at home and abroad. HPOM-based composite thin filmswith visible-light photochromism could be synthesized through compositing between HPOMand polymer or visible-light induced inorganic semiconductor nanoparticles. The influence ofthe component, content and preparation method on the structure and the visible-lightphotochromic behaviors of composite thin films have been investigated, and revealed theinteractions between the constitute, structure of composite films and the visible-lightphotochromic properties. According to the change transfer theory and energy level transitiontheory, the photo-production electron transfer mechamism in the POM-based compositesystem have been discussed, which provide fundamental basis for the development ofvisible-light photochromic system.I. Reversibly photochromic phosphomolybdic acid-ethyl cellulose （EC） composite filmwas prepared by hydrogen-bond interaction of dipping method, which was of wellphotochromic responsiveness and reversibility. Its structure, photochromism and mechanismwere studied by fourier transform infrared spectroscopy （FT-IR）, UV-visible spectroscopy,atomic force microscope （AFM） and X-ray photoelectron spectroscopy. FT-IR and AFMfindings showed that the phosphomolybdic acid-ethyl cellulose composite film was founddifferences in morphology and micro-structure before and after visible light radiation. FT-IRanalysis showed that Keggin phosphoaluminate molecular structure remained in this film.AFM findings indicated changes in surface topography before and after the phosphomolybdic acid-ethyl cellulose composite film was synthesized and illuminated. In visible light, thiscomposite film became from colorless to blue; UV-visible absorption spectroscopy showedthat electrons transferred from EC to heteropoly anions in the composite film and thephosphomolybdic anions scattered in EC macromolecules were able to be reduced toheteropoly blue under visible light radiation.II. Reversibly photochromic phosphomolybdic acid-polyvinylpyrrolidone （PVP）composite film was prepared by hydrogen-bond interaction of dripping method, which was ofwell photochromic responsiveness and reversibility. Its structure, photochromism andmechanism were studied by FT-IR, UV-visible spectroscopy, AFM and X-ray photoelectronspectroscopy. FT-IR and AFM findings showed that the phosphomolybdicacid-polyvinylpyrrolidone composite film was found differences in morphology andmicro-structure before and after visible light radiation. FT-IR analysis showed that Kegginphosphoaluminate molecular structure remained in this film. AFM findings indicated changesin surface topography before and after the phosphomolybdic acid-polyvinylpyrrolidonecomposite film was synthesized and illuminated. In visible light, this composite film becamefrom colorless to blue; UV-visible absorption spectroscopy showed that electrons transferredfrom PVP to heteropoly anions in the composite film and the phosphomolybdic anionsscattered in PVP macromolecules were able to be reduced to heteropoly blue under visiblelight radiation.III. Reversibly photochromic PMoA/SiO₂/ZnFe₂O₄composite films were prepared bysol-gel method, with PMoA molecules evenly distributed in these composite films. Thesefilms were of well photochromic responsiveness and reversibility. The structures,photochromisms and mechanisms of these films were studied by means of a series of trials.The results showed that PMoA/SiO₂/ZnFe₂O₄composite films were found differences inmorphology and micro-structure before and after synthesization. FT-IR analyses showed thatKeggin phosphomolybdic molecular structure remained in these composite films, which builta charge-transfer bridge between PMoA and ZnFe₂O₄. AFM findings indicated significantchanges in surface topography before and after PMoA/SiO₂/ZnFe₂O₄composite films weresynthesized and illuminated. In visible light, composite films became from colorless to blueand the heteropoly acid was reduced to the heteropoly blue. XPS findings indicated that thevisible light excited the ZnFe₂O₄to generate photoelectrons to lead to a photoreduction ofphosphomolybdic acid to heteropoly blue. The photochromic process in the system wasfollowed by the mechanism of photoelectron transfer.IV. A multilayer hybrid film fabricated from phosphomolybdic acid （denoted PMoA） and polyacrylamide （denoted PAM） by LBL technology shows photochromism under UVlight and visible light irradiation. With atomic force microscopy （AFM） and infrared spectra（IR）, the microstructure and composition of the hybrid films were studied. By means ofultraviolet–visible spectra （UV–vis）, X-ray photoelectron spectra （XPS） and electronresonance spectra （ESR）, the photochromic properties and mechanism of the multilayer filmswere investigated. It suggested that the multilayer films are uniform, dense and highlyadherent to the substrate with UV light and visible light phtochromism.更多还原