【作者】 刘春艳；

【导师】 王金渠；

【作者基本信息】 大连理工大学 ， 化学工艺， 2006， 博士

【摘要】 有序介孔薄膜材料因其独特的优点及其巨大的潜在应用,正成为材料科学家们的研究热点。介孔薄膜是指孔径位于2～50 nm之间的多孔无机膜,它不仅具有无机膜良好的化学稳定性、机械强度大、极好的耐热性、好的抗菌性能、无毒等优点,还具有普通无机膜所不具有的特殊的尺寸效应、功能性等优点。有序的介孔无机膜在膜反应器、超滤分离、纳米材料的制备、选择性电极、传感器、电致变色装置和低介电常数微电子绝缘层等方面的应用有着巨大的潜在优势。 仿生合成是无机材料合成发展的新趋势,将成为21世纪合成化学中的前沿领域,仿生合成技术（Biomimetic Synthesis）是一种崭新的无机材料合成技术,模拟生物矿化过程,通过有机大分子和无机物离子在界面处的相互作用,从分子水平控制无机物相的析出,从而获得具有特殊的多级结构和组装方式的无机材料,使材料具有优异的物理和化学性能。 本论文采用仿生合成的技术对有序介孔氧化硅薄膜的制备和表征进行了研究和探讨。本文模拟生物矿化过程,以两亲的有机大分子的自组装体为模板,调控无机物前驱体的成核和生长,在气.水界面和粗糙孔的α-Al₂O₃陶瓷管上仿生合成出了介孔氧化硅分子筛膜,并做了大量的XRD、SEM、TEM、TGA、物理吸附等表征,主要得到如下的结果和结论。 1.以两亲的表面活性剂的六方相液晶为模板,于室温下在气/水界面上成功地制备了孔道为一维的六方相介孔氧化硅薄膜。详细考察了物料配比、晶化时间、搅拌强度等不同条件对非担载薄膜制备的影响。研究结果表明,溶液的酸度及表面活性剂的用量对成膜的影响较大,酸度大时,膜薄,易破裂:表面活性剂的用量大时,在膜层中很容易富集CTAB的晶体。溶胶组成中表面活性剂浓度的大小可以调控膜孔径的大小,表面活性剂的浓度越小,所合成的膜孔径就越小。搅拌强度对膜的组成结构具有较大的影响,强搅拌时所合成的膜为单一孔径的六方相介孔SiO₂膜;而搅拌强度弱时,在一定的物料配比下能够制备出复合孔径的SiO₂膜。物料配比不同时,合成最优膜所需的晶化时间不同。在无机物种的浓度相差不大的情况下,溶液的酸度越大,成膜越快,得到最优膜所需的晶化时间越短。随着晶化时间的延长,SiO₂膜经历一个从无序到有序再到有序度降低的过程。SEM测试表明膜的上表面光滑,下表面较粗糙,证明膜的生长是从表面更多还原

【Abstract】 The ordered mesostructured membrane materials owing to their superior properties and great potential applications are becoming research focus in the material chemistry field. Mesoporous inorganic membranes with pore diameter of 2 50 nm not only have excellent thermal and chemical stability that inorganic membranes possess but have regular arrays of uniform channels and the dimensions can be tailored. The ordered mesoporous inorganic membrane is a promising material for membrane-based separation processes, catalysts, and chemical sensors, etc.Biomimetic synthesis has now become a promising field in inorganic materials chemical research. Biomimetic synthesis inspired by the biomineralization involves the controlled formation of inorganic materials with organic assembly as template, and the production of inorganic materials with special microstructure or mesostructure and excellent physical and chemical properties.The main works of this thesis are oriented mesoporous silica membranes are synthesized at air-water and solid-water interfaces by a surfactant-based supramolecular templating technique and characterized by XRD SEM TEM TGA N₂ adsorption and gas permeation experiment. The main results are as follows:1. Hexagonal mesostructured silica membranes have been synthesized at air-water interfaces by a surfactant hexagonal liquid crystal templating technique under quiescent aqueous acidic conditions. The influencial factors on membrane synthesis were investigated by XRD SEM and TGA studies. The growth of as-synthesized membrane involves two stages-the induction period and the subsequent rapid growth of a free-standing membrane. The induction period is dependent upon the concentration of the acid and observed induction period became longer when solution acidity reduced. And low acidity favors the growth of thick membrane. CTAB crystal diffraction peaks are observed in XRD pattern of as-synthesized membrane when surfactant concentration is high in solution, indicating that rich surfactant is in as-synthesis membrane layer. The influences of agitation intensity on crystal phase andsynthesis time on mesostructured order are observed by XRD studies. As-synthesized membrane goes through a transition from disorder to order and then to order reduced. SEM images show that superior surface of the free-standing membrane was smooth, however, inferior surface of it was gathered with rod-like particles. It was concluded that the membrane nucleated around hemi-micelles of surfactant located at the air-water interface and grew by coaggregation of the surfactant and silica into the water phase. It can also be estimated that the average thickness of the membrane is about 20 jam. TGA datas show that the decomposition of the surfactant in air involves three steps, and the total weight loss was about 65%.2. Mesoporous silica MCM-48 membranes have been synthesized on a coarse-pore a-AI2O3 ceramic tube through interfacial silica-surfactant self-assembly process. The membranes and powders were characterized by XRIX SEM^ TEM> TGAx N2 adsorption and gas permeation experiment. X-ray diffraction （XRD） results showed the membrane possessed a periodic mesostructure. The N2. adsorption and desorption isotherms also showed that the membrane was a typical mesoporous material with pore channel size of about 2.74 nm. The TGA experiment proved that the removal of the surfactant is a stepwise mechanism. The permeability of the calcined mesoporous MCM-48 membrane was evaluated by the permeation of single gases （H2 and N2） with pressure drops across the membrane of 40 240 kPa. The permeation of these gases through the calcined MCM-48 membrane was strongly governed by Knudsen diffusion. The permeance of the single gas was independent of the pressure drop, indicating that there was no contribution of viscous flow to the total permeation. This result supports that there exist no large pinhole and crack in the mesoporous MCM-48 membrane, in agreement with SEM observation.更多还原