多孔超支化共轭高分子纳米粒子的可控制备及其爆炸物传感研究

Most fluorescence film sensors based on linear conjugated polymers for explosive detection have the low sensitivity and slow response because of the poor diffusion of low-volatile explosive molecules inside conjugated polymer films. Hyperbranched conjugated polymers are considered as a promising candidate for fluorescence film sensors due to their three-dimensional structure with porous cavity. In this project, we plan to develop solution-processible porous hyperbranched conjugated polymer nanoparticles by Suzuki polymerization in miniemulsion for a kind of highly selective, highly sensitive and fast response fluorescence film sensors for explosive detection. The combination of “molecular wires” effect of the π-conjugated backbone and the enrichment effect of the inner porous cavity will improve their sensitivity and response speed toward TNT, DNT, and other explosives. In addition, the selectivity toward explosives can also be improved by the chemical modification of their numerous terminal reactive groups. Through the fine tuning of their electronic structures, porous structures and terminal structures, we hope to fabricate fluorescent porous hyperbranched conjugated polymer nanoparticle films with efficient diffusion for explosive detection. The above studies will provide the deep understanding for the relationship between molecular structure (backbone, side chain and terminal unit), microstructure (particle size and morphology) and explosive sensing properties (sensitivity, selectivity and response speed).

针对线型共轭高分子薄膜传感因通透性差导致爆炸物传感灵敏度偏低、响应速度较慢等瓶颈问题，具有多孔结构的超支化共轭高分子由于三维共轭骨架呈现独特的多孔空腔结构特征，能够为解决上述问题提供创新机遇。本项目旨在通过乳液聚合发展具有溶液加工特性的多孔超支化共轭高分子纳米粒子，利用共轭骨架的分子导线信号放大效应和内部多孔空腔的富集功能，提高TNT、DNT等爆炸物检测的灵敏度与响应速度，通过丰富末端端基的化学修饰提高爆炸物检测的选择性，发展一类高选择性检测爆炸物、且具有高灵敏度和快速响应的多孔超支化共轭高分子纳米粒子薄膜传感材料。围绕电子结构、多孔结构、端基结构三个方面实施结构调控，构建选择性检测爆炸物的高通透性多孔粒子荧光薄膜，期望建立分子结构（骨架、侧链、端基）、微观结构（粒子尺寸、粒子形貌）和爆炸物传感性能（灵敏度、选择性与响应速度）的内在关联，形成具有国际特色和国际影响力的研究成果。

本项目基于A3+B2型单体的细乳液Suzuki聚合方法，通过发展新型A3型单体及调控端基结构，获得了一系列多孔超支化共轭聚合物纳米粒子材料，并研究其在溶液与薄膜态的光物理性质，进而探索其荧光传感行为。（1）通过对多孔超支化共轭聚合物纳米粒子进行封端反应及后官能化反应，引入亲水性基团及传感功能单元作为纳米粒子的功能端基，调控纳米粒子的分散性与传感性能，用于芳香硝基爆炸物及易挥发有毒有害蒸汽的高灵敏荧光检测，对TNT的检出限达到3.7 nM，猝灭常数为1.21x106 M-1，比相应的线型共轭聚合物纳米粒子的猝灭常数高两个数量级，是共轭聚合物和共轭聚合物纳米粒子荧光传感器检测水相中TNT的最好结果；对苦味酸检测限达到0.78 nM （0.18 ppb），低于世界卫生组织对饮用水中TNP的最低允许含量（1 ppb）。（2）通过发展基于亚酞菁和三聚吲哚等新型结构的A3型功能单体，制备了新型多孔共轭聚合物及超支化聚合物及其纳米粒子，同时还利用这些新型A3型功能单体构建了具有优异发光性能及高效空穴传输性能的新型光电功能小分子及超支化聚合物材料，研究了它们在电致发光器件中的应用，为进一步发展具有新结构、新机制和新性能的多孔超支化共轭高分子及其纳米粒子，并拓展其应用领域奠定了基础。