【作者】 郭娟；

【导师】 陈道勇；

【作者基本信息】 复旦大学 ， 高分子化学与物理， 2012， 博士

【摘要】 规整排列的二炔分子在紫外光、X射线或丫射线等照射下发生拓扑聚合反应得到聚二炔。受到外界刺激时,聚二炔会发生肉眼可见的颜色转变,一般从蓝色变成红色,并且伴随着荧光的出现。这种独特的性质使得聚二炔体系在传感器领域有着广阔的发展前景。但是,聚二炔的不可逆变色行为严重制约了聚二炔类传感器的重复使用。很多研究工作者致力于可逆变色聚二炔的制备。最近,我们报道了使用商品化二炔酸(10,12-pentacosadiynoic acid, DA)和商品化聚合物聚乙烯基吡咯烷酮(PVP)作为原料,通过制备特殊的层状纳米结构,在纳米结构中所有聚二炔酸(poly(10,12-pentacosadiynoic acid), PDA)侧链端基的羧基官能团都“绑定”到PVP基质上,得到了完全可逆热致变色的PDA。本论文中,我们系统地研究了PDA的可逆机理和影响其可逆性的因素,且在另一种聚合物基质中得到了完全可逆热致变色的PDA。另外我门在有机小分子基质(SOC),如三聚氰胺(MA)中也得到了完全可逆热致变色的PDA。首先,通过DA和MA分子间相互作用制备DA/MA纳米复合物,随后光照聚合得到可逆热致变色PDA/MA纳米复合物。DA/MA纳米复合物是通过简单的和特定的混合方法和退火处理得到的。另外,我们还利用PDA/SOC纳米聚集体作为一种独特的选择性目标金属离子识别的检测平台。选择性金属离子识别是通过环境中或者纳米聚集体壳层中的SOC捕获非目标金属离子实现的。这个工作为选择性金属离子识别提供了一个新概念。本论文的研究工作可以分为以下三个部分：1.可逆热致变色PDA/聚合物共混物的制备通过研究聚合物种类、混合方法、原料混合比例、退火温度和退火时间等,我们提出在具有相对较高玻璃化转变温度、非离子化的水溶性聚合物作为聚合物基质时,完全可逆热致变色PDA需要通过制备特定的层状纳米结构,在该纳米结构中每一个结晶的DA双层结构必须以非共价键形式连接到聚合物基质上,随后光照聚合该DA/聚合物共混物得到。此外,我们发现除了PVP外,在聚乙烯醇(PVA)中也可以得到完全可逆热致变色PDA。同时,我们还系统研究了可逆机理和影响可逆性的因素。2.可逆热致变色PDA/三聚氰胺纳米聚集体分散液的制备我们成功地在三聚氰胺(MA)基质中实现了不可逆变色PDA在PDA/MA纳米复合物中可逆热致变色的转变。首先,通过简单的和特定设计的混合方法和退火处理得到具有层状结构的DA/MA纳米复合物。在该层状结构中,每一个DA双层结构插入到两个MA层中,且所有结晶DA的羧基官能团都“绑定”到MA基质上。随后,在光照聚合得到可逆热致变色PDA/MA纳米复合物中,所有PDA侧链端基的羧基官能团都“绑定”到MA基质上。“绑定”作用提供了PDA可逆热致变色的回复力。3. PDA/SOC纳米聚集体作为选择性金属离子检测平台的应用我们发展了一种独特和简单的基于PDA/SOC纳米聚集体的选择性金属离子检测平台的方法。相对于传统的通过检测平台和目标金属离子间专一的相互作用实现选择性金属离子识别的方法,本论文中选择性金属离子识别是通过环境和聚集体壳层中SOC捕获非目标金属离子,使其远离检测平台,同时躲避SOC捕获的目标金属离子靠近检测平台,且造成光学性质的改变而实现的。利用这个概念,我们分别制备了选择性P2+识别的PDA/甘氨酸纳米聚集体分散液和选择性Zn2+识别的PDA/硼酸纳米聚集体分散液。我们相信使用SOC或同时使用PDA的这个概念可以得到更多的选择性金属离子识别平台。更多还原

【Abstract】 When properly packed in the solid state, diacetylene monomers can be topochemically polymerized into polydiacetylene by UV, y-or strong X-ray irradiation. Polydiacetylenes are promising in the uses as chemical and biological sensors based on their color and fluorescent responses to environmental stimuli. However, the color and fluorescent changes of the polydiacetylenes are usually irreversible, which prevent them from being repeatedly used. Great efforts have been devoted to fabrication of reversible polydiacetylenes. Recently, we reported that started from a commercialized diacetylene10,12-pentacosadiynoic acid (DA) and a commercially available polymer poly (vinyl pyrolidone)(PVP), without any chemical modification, the reversibility of PDA can be realized in PVP matrix through tethering all the carboxyl groups of PDA side chains to the polymer matrix; the tethering was realized by forming the PDA/polymer blend with an intercalated structure. In this thesis, we studied systematically the mechanism and the factors that affect the reversibility, and succeeded in finding an additional polymer that can lead to the reversibility. Besides, we found that melamine (MA), a small organic compound (SOC), can interact with DA molecules to form the DA/MA nanocomposite whose topochemical polymerization leads to the completely reversible PDA/MA nanocomposite; simple but deliberately designed mixing and annealing processes were applied for preparing the DA/MA nanocomposite. Additionally, we used PDA/SOC nanoaggregates as unique platforms for selective detection of targeted metal ions; the selectivity was realized through catching the untargeted metal ions by SOC molecules either in the environment or in the shell surrounding the nanoaggregates. This provides a novel concept for detecting metal ions selectively. Specifically, this thesis includes following three sections:1. Preparation of the PDA/polymer blends being completely reversible in the thermochromism:In this section, by testing different polymer matrices, mixing methods, annealing temperatures, and annealing times, we confirmed that, when a water-soluble and nonionic polymer that has a relatively high glassy transition temperature was used, the complete thermochromic reversibility of PDA can be realized in the polymer matrix by preparing the DA/polymer blends with a nanostructure in which every DA crystallized bilayer is tethered to the polymer martrix and then topochemically polymerizing the blends. Besides of PVP, we found poly (vinyl alcohol)(PVA) can aso be used as the matrix to realize the reversibility. The mechanism and the factors affecting the reversibility were systematically studied.2. PDA/MA nanoribbons with the complete reversibilityIn this section, we prepared successfully the poly(10,12-pentacosadiynoic acid)(PDA)/melamine (MA) nanocomposite nanoribbons in which PDA, which is irreversible in its pure form, becomes completely reversible in the thermochromsim. PDA/MA nanocomposite is the product of topochemical polymerization of10,12-pentacosadiynoic acid)(DA)/MA nanocomposite. The DA/MA nanocomposite that can lead to the PDA/MA nanocomposite with the complete reversibility was prepared from simple but deliberately designed mixing and annealing processes. The as-prepared DA/MA nanocomposite has a lamellar structure in which a DA bilayer is sandwiched between two MA layers, and all the carboxyl groups of the DA crystallized bilayers are tethered to the MA layers. The PDA/MA nanocoposite derived from the DA/MA nanocomposite also has a lamellar structure. It is significant that, in the PDA/MA lamellar structure, all the side groups of PDA are tethered to MA layers, which makes the PDA within the nanocomposite thermochromically reversible.3. Application of PDA/SOC nanoaggregates as unique platforms for detecting metal ions selectively:We developed a novel and simple method for detecting metal ions selectively using PDA/SOC nanoaggregates as the platforms. Different from existed methods in which the selective detection was realized through the selective interaction between sensor and the targeted metal ions, the method developed in this thesis achieved the selectivity through catching the untargeted metal ions by the SOC molecules to prohibit their interaction with the sensor. As the result, the metal ions that are inert to the interaction with SOC molecules can reach the sensor and cause the fluorescene and color responses. This provides a novel concept for detecting metal ions selectively. Ultilizing this concept, Pb2+-selective sensor based on the suspension of PDA/glycine aggregates and Zn2+-selective sensor based on the suspension of PDA/boric acid aggregates were prepared. We belived that, through changing SOC or even the PDA this concept can be further extended to selective detection of other metal ions.更多还原