基于氮杂环类离子液体的低聚型超两亲分子的构筑及自组装行为研究

Oligomeric surfactants have been widely used in many fields due to their superior physicochemical properties and special self-assembly behaviors. However, complicated synthesis procedures severely limit the development and applications of the novel surfactants. If surfactants are constructed via non-covalent interactions, complicated synthesis procedures can be effectively avoided. The novel kind of amphiphiles formed via noncovalent interactions, namely superamphiphiles, not only have simple and green synthesis procedures, but also exhibit various architectures and controlled self-assembly behaviors. In this project, we will construct oligomeric superamphiphiles through noncovalent interactions, and then systematically study their self-assembly behaviors in aqueous solutions. Based on their unique physicochemical properties, N-heterocyclic ionic liquids will be acted as building blocks of oligomeric superamphiphiles. Firstly, oligomeric superamphiphiles with various architectures will be constructed through suitable design of building blocks, which is intended to fabricate self-assemblies with novel structures and functions. Then, responsive groups will be introduced to the building blocks of superamphiphiles to obtain responsive self-assemblies. The effect of noncovalent interactions and structures of building blocks on the self-assembly behaviors of oligomeric superamphiphiles will be investigated in detail, which is helpful to achieve controlled self-assembly and disassembly of oligomeric superamphiphiles.

低聚表面活性剂，因其优异的物化性能以及丰富的自组装行为，在诸多领域展现出独特的应用价值。然而，复杂繁琐的合成过程严重制约了低聚表面活性剂的发展和应用。若通过非共价键作用构筑两亲分子，可有效避免复杂的合成路线。基于非共价键构筑的新型两亲分子，即超两亲分子，不仅合成路线绿色简便，还具有丰富的拓扑结构以及可控的自组装行为。基于此，本项目拟通过非共价键作用构筑低聚型超两亲分子，并系统研究它们在水溶液中的自组装行为。基于氮杂环类离子液体的独特性能，拟以其作为低聚型超两亲分子的结构基元。一方面，通过合理的基元设计，构筑具有丰富拓扑结构的低聚型超两亲分子，进而组装得到结构新颖的分子有序组合体；另一方面，拟在结构基元上引入 pH 敏感基团，最终实现响应型功能组装体的制备。重点考察非共价作用以及构筑基元的结构变化对低聚型超两亲分子自组装行为的影响，推动实现分子有序组合体的可控自组装与解组装。

超两亲分子，基于非共价键构筑而成，其构建过程简便、拓扑结构多变、易功能化、多级组装结构丰富可控，从而为构筑结构新颖功能多样的超分子组装体提供了崭新的基元。本项目以氮杂环类离子液体为结构基元，通过合理的基元设计，构筑具有丰富拓扑结构和自组装行为的低聚型超两亲分子，并在结构基元上引入刺激响应基团，实现低聚超两亲分子的可控自组装；在此基础上，明确构筑基元的结构变化以及非共价键作用对超两亲分子自组装行为的调控作用。该项目的开展，一方面打破了共价合成对低聚型表面活性剂的制约，为低聚表面活性剂的快速发展开辟新的途径；另一方面，也将进一步完善分子有序组合体理论研究，并为功能超分子材料的构建和应用提供理论依据和实验指导。本项目取得了一系列有意义的研究成果。首先，设计得到bola型、三聚型、Y型等不同结构类型的构筑基元，通过 π-π 堆积、静电引力、氢键、动态共价键等多种非共价作用成功构筑了具有丰富拓扑结构和类型的低聚型超两亲分子（Gemini型、双尾型、三聚型、四聚型、阳离子型、阴离子型等），并进一步组装得到了结构新颖的分子有序聚集体（囊泡、蠕虫状胶束、纳米管、纳米环、层状相等）；其次，通过调节构筑基元的结构性质（柔性、疏水性、芳香性、构象等），明确了构筑基元的结构变化以及非共价键作用类型对超两亲分子自组装行为的影响，实现了超两亲分子的可控自组装与解组装；最后，通过在构筑基元中引入氨基、醛基等功能基团，实现了外界刺激（pH、温度、CO2等）对低聚型超两亲分子拓扑结构的有效调控，进而组装得到多种智能超分子组装体。