新型水分散超支化共轭聚合物纳米粒子的可控制备与传感性能

As fluorescent sensing materials, conjugated polymers (CPs) based on π-conjugated “molecular wires” effect can greatly amplify the fluorescent sensing signal. However, most of fluorescence sensors based on linear conjugated polymers and linear conjugated polymer nanoparticles exhibit low sensitivity to the organic contaminants in water due to the serious interfering by water molecules. Hyperbranched conjugated polymers are considered as a promising candidate for developing fluorescence sensors due to their three-dimensional structure with hydrophobic cavity, which is helpful for capturing the contaminants in water, especially the organic contaminants by hydrophobic interaction. Moreover, hyperbranched conjugated polymers with a lot of terminal groups can be dispersed in water by functionalizing their terminal groups with hydrophilic groups. In this project, we plan to develop a series of novel water-dispersed hyperbranched conjugated polymer nanoparticles with large amount of hydrophilic terminal groups through Suzuki polymerization in miniemulsion and post-functionalization of nanoparticles. Based on the efficient hydrophobic enrichment interaction between the hydrophobic cores of nanoparticles and organic molecules, these hyperbranched conjugated polymer nanoparticles are expected to be used as novel fluorescence sensors with highly sensitive response to contaminants in water. We believe that, this study will pave a new way for development of conjugated polymer nanoparticles as highly sensitive fluorescent sensing materials.

共轭聚合物的荧光传感检测具有分子导线信号放大效应，但采用线型共轭高分子及其纳米粒子实施水体系中有机污染物的溶液检测，存在难以实现水溶性和水分子的干扰导致灵敏度较低的瓶颈问题。超支化共轭聚合物具有独特的分子结构（内部的本征三维结构和多孔结构、末端的大量端基），可以通过端基修饰引入亲水性基团实现水相分散，内部的本征疏水空腔对有机污染物进行有效富集，在构建水相检测污染物，特别是有机污染物的荧光传感器方面具有独特优势。本项目拟采用乳液Suzuki聚合反应与亲水性基团后功能化相结合，发展系列具有亲水性末端基团和疏水内部空腔的水相分散超支化共轭聚合物纳米粒子。利用内部疏水空腔对有机小分子的疏水富集作用，大幅提升水相荧光检测的灵敏度，开发出一系列高灵敏度水相检测的超支化共轭聚合物纳米粒子荧光传感体系，形成具有国际特色和国际影响力的研究成果。

围绕超支化共轭聚合物纳米粒子的可控制备和荧光传感性能的研究主题，发展了细乳液Suzuki聚合的封端反应以及纳米粒子后功能化反应，开发出系列水分散及可溶液加工的超支化共轭聚合物纳米粒子，在水相荧光检测和薄膜及光纤探针检测两方面取得了创造性的研究成果。（1）有效地实施了超支化共轭聚合物纳米粒子的亲水基团功能化，分别制备出具有磺酸盐端基、季铵盐端基和磷酸酯侧链的超支化共轭聚合物纳米粒子，获得了水分散超支化共轭聚合物纳米粒子荧光传感材料体系。利用疏水富集与静电作用的协同效应的策略和利用端基与分析物之间的高效化学反应的策略，分别实现了水体系中痕量TNT和TNP的高选择性荧光猝灭检测和有机胺的荧光增强检测，为实现水溶液中共轭聚合物的高灵敏和高选择性荧光传感提出了新思路。（2）首次开发出以富电子的和C3-对称性的平面三聚吲哚为核心单元的可溶液加工的超支化共轭聚合物纳米粒子，解决了三聚吲哚类共轭聚合物难以溶解和不能溶液加工的问题，发展出检测TNT蒸汽的荧光猝灭型光纤探针和毒性肼蒸汽的荧光增强型光纤探针，并获得了高灵敏度和快速响应等优异的检测效果，为爆炸物及毒性气体荧光检测的器件应用奠定基础。