基于对苯撑乙烯交替共聚物的合成、自组装及微观形貌调控

Conjugated polymer-based functional materials have been widely used in optoelectronics. To improve the performance of optoelectronic devices, optimization of polymer properties has become the main approach. Studies have shown that formation of well-ordered nanoscale polymer microstructure can facilitate intermolecular energy transfer and charge transport, which is another important factor to affect the photoelectric conversion efficiency. However, research on the interaction between the conjugated polymer chains and aggregate morphology is still relatively few. In this context, this project utilizes a bottom-up synthetic strategy to develop a series of well-defined flexible morphon-linked poly(p-phenylenevinylene) (PPV) alternating copolymers through introduction of flexible alkyl chain monomer into the PPV backbone. This can regulate the conjugation length of the chromophore at the molecular level, avoiding random defects-caused disruption of the backbone structure to form multiple chromophores with different conjugation lengths. At the same time, through weak bond interactions, the assembly structure was systematically controlled by variation of main-chain structure and side-chain groups. Additionally, multiple characterizations including single-molecular fluorescence spectroscopy were utilized to explore the relationship between the structure and morphology of the PPV copolymers. The successful completion of these studies will have an important positive impact on polymer morphology understanding and will provide basic theory to design new high-performance polymers, which can be applied to create improved energy technologies.

共轭聚合物构筑的功能材料在光电领域有着广泛的应用，其中聚合物结构的优化已成为提高光电器件性能的主要途径。研究发现，实现聚合物链纳米级有序性的微观形貌，有利于分子间的能量转移和电荷迁移，是影响器件光电效率的重要因素；然而，对于共轭聚合物分子链之间的相互作用及聚集态微观形貌的研究还相对较少。本项目拟采用自下而上有机合成的方法，将柔性烷基链引入到对苯撑乙烯聚合物骨架中，合成一系列柔性形态单体相连的对苯撑乙烯交替共聚物。这样可以在分子水平上对生色团的共轭长度进行调控，避免了由于随机缺陷造成主链结构破坏而形成多个具有不同共轭长度的生色团。同时，通过改变主链结构和侧链基团，利用弱键作用调控其组装体的结构；结合单分子荧光光谱等表征手段，探讨对苯撑乙烯交替共聚物结构与微观形貌之间的关系。本项目的成功完成将对聚合物微观形貌的理解产生深远的影响，为新型高性能聚合物的设计提供了理论依据，引发能源技术革命性创新。

π-共轭有机材料，成本相对低廉，来源广泛，易于加工，在有机发光二极管，有机场效应晶体管，化学传感和生物成像等方面有着广泛的应用。其中，对苯撑乙烯低聚物由于具有明确的结构和化学纯度，易于通过化学修饰改变光物理和电子性能，受到了人们的普遍重视。通过自下而上的有机合成，本项目设计制备了具有不同主链骨架、共轭长度以及侧链基团的对苯撑乙烯低聚物，并通过紫外吸收，荧光发射波谱等手段初步研究了其光物理性质。研究表明，该类化合物具有良好的荧光特性和聚集诱导发光现象，有望用于发光材料的研究。三年期间，在Org. Lett., Chin. Chem. Lett., J. Org. Chem.等期刊上发表SCI论文27篇（标注基金）。