绿色介质辅助竞争性氢键调控纳米组装材料的性质及其机理研究

In this work, a new type of nano fluorescent composites (NFC) with controlled location and distribution of the dye unit, is to be developed via the self assembly between dye unit and the block copolymer in a green media, the CO2 expanded liquids (CXLs). The present work focuses on the preparation of the NFC with controlled structures and photoluminescent properties through the self assembly modulated by the competitive hydrogen bond interactions with the assistance of CXLs technology. Different and competitive type of hydrogen bonds will be involved in the system between the dye unit and block copolymer or the CXLs solvent, and the CXLs tunable intermolecular interactions have critical effect on the regulation of photo-responsive behavior of the NFC. Through the variation of parameters such as CXLs composition and pressure, the polymer species and concentration as well as composition, the solvated configurations of polymer chains in micelle can be easily modulated, which further induces the change in the relative affinity between hydrogen bond donors and acceptors, and leads to the strength and amount tuning of the competitive hydrogen bonds in the system. The information of NFC structures and the competitive hydrogen bonds can be obtained via the simulation models construction along with the computational simulations. We believe that the experimental and simulation studies will not only contribute to the molecular level knowledge of the influence of CXLs green media on the competitive hydrogen bonding interactions, but also help uncover the modulation mechanism of their influence on the self assembly behavior. Such studies provide a promising green pathway for the development of novel optical polymer materials with high efficiency via the non-covalent interaction method, and meanwhile offer important theoretical support for the green self assembly technology and engineering.

申请项目拟利用绿色介质二氧化碳膨胀液体（CXLs）辅助竞争性氢键调控染料单元与嵌段共聚物的自组装，制备一种染料单元定位及分布可控的新型纳米荧光复合物 (NFC)，实现NFC的结构及发光性能的可控制备。研究体系含有竞争性氢键作用，染料单元既可与共聚物产生氢键，也可与CXLs溶剂发生氢键缔合，其中利用CXLs调控分子间相互作用是实现 NFC 光学响应性能可控的关键因素。通过改变CXLs的组成和压力、共聚物的种类、浓度及组成等因素来调节聚合物链段的溶剂化构型，诱导体系中氢键供体和受体间的亲和力的改变来调控竞争性氢键的强度和数量。构建系列模型进行模拟计算，获得NFC结构及竞争性氢键作用的信息。借助实验及模拟计算研究，从分子水平揭示绿色介质辅助的竞争性氢键的变化规律及其对组装行为的调控机理，为基于非共价键方法研发新型聚合物高效发光材料开辟一条崭新的绿色途径，为实现绿色自组装技术及工艺提供理论指导。

I. CXLs中嵌段共聚物及其与荧光单元自组装结构及功能-实验及模拟计算.使用密度泛函理论（DFT）和耗散粒子动力学（DPD）方法结合实验对353.2 K时CXLs-荧光单元-嵌段共聚物混合体系中形成的自组装荧光复合物(SAFCs)的组装结构和发光机理进行了实验-模拟计算的协同研究。考察了嵌段共聚物的组成、选择性CXLs溶剂的种类及压力对SAFCs形貌结构及发光性能的影响。其中DPD模拟侧重于揭示SAFCs随压力变化的定量结构信息，而DFT计算侧重于获得影响SAFCs发光性能的氢键信息。通过DPD模拟，获得了体系粗粒化珠子间的Flory-Huggins参数、排斥参数、聚合物链段的回转半径等微观结构信息随压力的变化趋势，揭示了CXLs的压力对SAFCs的形貌结构的调控机理。根据DFT计算对有效影响SAFCs发光性能的竞争性氢键类型进行了甄别。DPD模拟和DFT计算相结合，可以定量地筛选出能够有效调节SAFCs结构及发光性能的关键因素。通过实验协同模拟计算的对比研究，发现改变CXLs的压力可以有效调控SAFCs组装结构的形貌及竞争性氢键之数量，进而有效调控SAFCs的发光性能。提出了CXLs辅助竞争性氢键对SAFCs结构及发光性能的调控机理，有望为开发绿色自组装技术及工艺提供重要理论指导。.II. 高分子纳米荧光传感器的合成、胶束结构和性能-实验及模拟计算.合成了荧光标记的温度及pH传感器PNIPAM(MAh-4)-b-P4VP (PN4P)，实验方面考察了温度及溶液pH等因素对传感器在纯水或乙醇-水溶液中的胶束结构及其发光性能的影响，计算方面利用耗散粒子动力学（DPD）模拟了该传感器在水溶液中的胶束结构对pH及温度的响应，提出了合理的传感器双重刺激响应的发光机理。本工作为设计新型温度及pH传感器并拓展其在生物传感和刺激响应材料方面的应用提供了新策略。.III. 电极材料及CO2利用.开展了电催化还原CO2的研究，考察了非贵金属催化剂的制备方法、组成及结构、载体类型、电解液组成、施加电压等因素对反应选择性的影响，推测了反应路径和反应机理，为实现碳循环和减轻环境污染提供了新方法和新策略。.此外，我们还进行了钠离子电池负极材料的制备及其储钠性能的探索性研究。