【作者】 刘为；

【导师】 雷家珩；

【作者基本信息】 武汉理工大学 ， 应用化学， 2006， 硕士

【摘要】 本论文选择在光学器件、分离、催化等领域有重要应用前景的有序介孔氧化硅薄膜作为研究对象。在制备有序介孔氧化硅薄膜的基础上,通过在介孔氧化硅薄膜中组装金属、半导体纳米粒子,得到具有特定光学功能的介孔复合薄膜。主要工作包括: 以非离子型烷基聚氧乙烯醚表面活性剂为模板,采用挥发自组装工艺制备介孔氧化硅薄膜。在选定的条件下,通过改变表面活性剂的浓度,分别制备出有序三维立方、二维六方和蠕虫状结构的介孔氧化硅薄膜。在不同种类酸的存在下,以非离子型烷基聚氧乙烯表面活性剂为模板分别制备出有序三维立方、二维六方和无序结构的介孔氧化硅薄膜。采用小角X射线衍射和高分辨率透射电镜研究了合成条件对产物介孔结构的影响,并对作用机理进行了探讨。 采用Sol-gel浸涂法,以烷基聚氧乙烯醚为模板剂和Ag⁺锚固剂、正硅酸乙酯为无机前驱体,在反应溶胶中加入Ag⁺离子,浸涂成膜后150℃热处理,一步直接合成了装载Ag纳米粒子的介孔二氧化硅薄膜。以Uv-vis表征了在合成过程中Ag纳米粒子的形成及其表面等离子体共振吸收峰的变化,小角XRD测试表明薄膜为有序的六方介孔结构,晶胞参数为4.26nm。样品的TEM和EDS图谱证实薄膜有序介孔中单分散银纳米粒子的存在和介孔对银纳米粒子的限域生长效应。 通过一步共聚法合成孔道表面具有巯基的有机一无机杂化介孔薄膜。以得到的有序介孔杂化薄膜为模板,浸渍吸附Cd²⁺离子,N₂气氛下高温煅烧,孔道内反应生成CdS纳米粒子,从而得到CdS/介孔氧化硅纳米复合薄膜。小角XRD显示在生成纳米粒子后,薄膜的有序介孔结构未受到破坏。TEM直观地证实CdS粒子在孔道内限域生长,粒子的大小约为3纳米,与孔的直径相当。EDS表明薄膜内CdS的含量约为7%,Cd和S元素组成相当。Uv-vis吸收光谱检测到CdS/介孔氧化硅纳米复合薄膜具有明显的量子尺寸效应。更多还原

【Abstract】 Ordered mesoporous silica films, which have important potential applications in optical device, separation and catalysis fileds, have been chosen as the research object of this thesis. On the bases of the formation of ordered mesoporous silica films, metal and semiconductor nanoparticles were incorporated to the mesoporous silica films. Mesoporous composted films with special optical functions are obtained. The main contents are as follows.Mesoporous silica films are fabricated by an evaporation induced self-assembly （EISA） procedure using the nonionic alkyl （ethylene oxide） surfactant as a template. By change the concentration of surfactant in a chosen conditions, Well-ordered 3D-cubic, 2D-hexagonal, and worm-like mesoporous silica films have been synthesized. Also Well-ordered 3D-cubic, 2D-hexagonal, and disordered mesoporous silica films have been synthesized with the same concentration of non-ionic surfactants, depending on the kind of acids. The effects of conditions on the mesophases were investigated by X-ray diffraction and high-resolution transmission, electron microscope. The action mechanism has also been discussed.Mesoporous silica films embedded with Ag nanoparticles have been synthesized directly by a Sol-gel dip-coating process, combining alkyl （ethylene oxide） surfactant as temple and tetraethoxysilane as inorganic precursor. The addition of Ag⁺ ions to the reaction sol prior to the formation of films, followed by the heat treatment at 150℃ led to the creation of Ag nanoparticies. The formation of Ag nanoparticles and the change of its surface plasma resonance absorption were characterized by Uv-vis. The small angle XRD test indicates that the films had an ordered hexagonal mesoporous structure, which the unit cell parameter was about 4.26nm. The TEM graphs and EDS spectra of the samples have verified directly the presence of mono-dispersed Ag nanoparticles within the films, due to the confine effects of mesopores to them.Binary semiconductor CdS nanoparticles have been prepared inside the channels of mesoporous silica film using an in situ formation method. The approach combines formation of the origanic-silica hybrib mesoporous filim with thiol groups in the channel surface, absorption of Cd²⁺, and heating in N₂ atmosphere at high temperature. The mesostructure order was retained after the growth of the nanoparticles, as pointed out by small-angle X-ray diffraction measurements. Electron microscopy characterizations unambiguously demonstrate that the mesoporous structure allows to control the particle size and the organization of CdS nanoparticles. The mean particles diameter is 3 nm, which is compatible with the pore dimensions. And a blue shift is observed in UV-Vis absorption spectrum, indicating the quantum size effect of nanocrystalline CdS.更多还原