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多环芳烃的固液界面单层组装、光物理行为及其传感特性
Monolayer Assembly of Polycyclic Acromatics at Solid-Liquid Interfaces, and Studies on Their Photophysical Behaviors and Sensing Performances
【作者】 高莉宁;
【导师】 房喻;
【作者基本信息】 陕西师范大学 , 材料学, 2006, 博士
【摘要】 近年来,通过小分子在基质表面的单层有序组装而设计、制备新型功能薄膜材料受到人们的广泛关注,而将小分子化学键合到基质表面则是单分子层组装的重要方法之一。基于此,本实验室提出了以固液界面单层组装多环芳烃的超分子相互作用为基础的传感薄膜材料设计新思想,在此思想指导下通过改变基质的种类,变换传感元素等手段,设计、制备得到了一系列新颖的对水综合品质、硝酸盐、硝基甲烷、醇/水混合体系组成等敏感的传感薄膜材料。 本论文在对二氧化硅基质表面自组装单层膜(self-assembled monolayers,SAMs)和荧光传感薄膜综述基础上,结合本实验室已有的研究工作,利用玻璃为基质,通过变换传感元素,调节连接臂长度,改变连接臂的亚结构等设计制备了多种对水体中二元羧酸、有机铜盐、Cu2+离子等敏感的传感薄膜材料。而且,所制备的多数传感材料具有选择性高、响应可逆、稳定性好、使用寿命长等优点,为后续器件化研究奠定了坚实的基础。具体来讲,主要完成了以下工作: (1)将分子识别的概念引入传感薄膜的设计、制备中,以芘为传感元素,通过含有二胺结构的柔性长臂将其通过SAMs固定于玻璃基质表面,分别得到了连接臂中包含有乙二胺或丙二胺结构单元的两种新型传感薄膜材料。在这种薄膜的设计中,有意地引入了能与羧羟基形成氢键的二胺结构,以期得到对二元羧酸具有良好传感性能的薄膜材料。通过多种技术对所得传感薄膜的组成和结构进行了表征,并结合静态荧光和分时荧光技术对固定化芘在干态和水相中的光物理行为作了深入的研究。结果表明,这两种薄膜表面的芘多数以基态二聚体的形式存在。传感实验表明,二元羧酸的加入均使得这两种传感薄膜的单体发射和激基缔合物发射同时增强,而一元羧酸的存在并不影响薄膜的荧光发射。产生这一结果的原因被归结于二元羧酸插入相邻连接臂之间,改变了芘在基片表面的空间分布,从而引起薄膜荧光发射效率的变化。实验还发现,二元羧酸加入后体系达到平衡的时间因二元羧酸链长的不同而不同。一般来讲,二元羧酸的链越长,加入后体系达到平衡的时间越长。连接臂中含有乙二胺和丙二胺结构单元的传感薄膜对二元羧酸响应的对比实验表明,含有丙二胺结构单元的传感薄膜对二元羧酸的响应时间明显缩短。 (2)考虑到在上述两种传感薄膜的设计、制备中,连接臂结构的微小变化都
【Abstract】 In recent years, monomolecular assemblies on solid surfaces have attracted growing attention due to their potential applications in creation of sensing films. Chemical immobilization of small molecules onto substrate surfaces is one of the important approaches to prepare monomolecular assemblies. Based upon this methodology, a new idea of designing sensing films based on the supramolecular interactions of polycyclic aromatics self-assembled on solid-liquid interfaces was proposed in our laboratory, and a series of novel sensing films, which are sensitive to the purity of water, the presence of nitrite in aqueous phase, nitromethane in methanol, ethanol or water, or the composition of the mixture of water and ethanol, were successfully created.On the bases of the above-mentioned research works and the reviews on self-assembled monolayers on silicon dioxide surfaces and fluorescence sensing films, several sensing films were designed and prepared by changing the sensing element, adjusting the length of spacers, and altering the sub-structures of spacers in this thesis, and these sensing films were proved to be sensitive to the presence of dicarboxylic acids, organic copper (II) salts, and copper (II) salts, respectively. Furthermore, their sensing ability, high sensitivity, ideal reversibility, and long lifetime make them worthwhile to be exploited further.First, the concept of molecular recognition was introduced into the design and preparation of sensing films, two novel photo-induced luminescence films have been prepared by immobilizing pyrene on glass plate surfaces via flexible long spacers, containing ethylenediamine or 1,3-dianinopropane and 3-glycidoxypropyltrimethoxy-silane. During the designing of the films, imino units were intentionally introduced into a spacer. Imino units were chosen due to their character to form hydrogen bond with carboxyhydroxy groups. It was expected that the specific interaction of the imino group with carboxyhydroxy group would result in insertion of dicarboxylic acids into
【Key words】 Pyrene; Anthracene; Self-assembled monolayers; Sensing properties; Dicarboxylic acids; Organic copper salts;