正交自组装构筑超分子智能水凝胶及其调控

The supramolecular crosslinking of polymer chains in water by dynamic non-covalent interactions has led to the development of novel supramolecular hydrogels. On account of the interesting properties such as stimuli-responsiveness, shape memory and good biocompatibility, these soft materials have drawn much attention in the fields of bio-medicine and smart materials. The project aims to construct supramolecular hydrogels with shape memory ability by employing ureidopyrimidinone-based self-complementary quadruple hydrogen bonding as cross-linking driving force. The project will focus on: (1) by providing hydrophobic micro-environment to UPy-UPy dimer and adjusting the cross-link density, the mechanic property and shape memory ability could be tailored. Meanwhile, by introducing the pillararene-based host-guest interaction which is orthogonal to quadruple hydrogen bonding, the hydrogels will be endowed swelling and shrinkage, multi-responsiveness properties. Thus, multi-functional smart hydrogels could be created. (2) Furthermore, by introducing tetraphenylethylene group with AIE effect to the polymer backbone, novel florescent supramolecular polymeric hydrogels could be constructed, which will provide a new window to drug delivery. This project is expected to not only explore new avenue to construct smart supramolecular polymeric hydrogels, but also provide new information for the research of shape memory materials and drug delivery.

通过动态的非共价键作用使聚合物链在水中进行超分子交联引导了一类新型的超分子水凝胶材料的诞生。这类软材料因具有诸如刺激响应性、形状记忆功能及良好的生物相容性而在生物医药、智能材料等领域引发了强烈关注。本项目将以基于脲基嘧啶酮（UPy）的自互补型四重氢键作为交联驱动力构筑具有形状记忆功能的超分子水凝胶：（1）通过对UPy-UPy模块提供疏水微环境进行保护和调节交联密度而裁剪式地调控水凝胶的力学性质和形状记忆功能，同时利用与四重氢键正交的基于柱芳烃的主客体作用赋予水凝胶更好的溶胀收缩性能和多重刺激响应性，以制备多功能的智能水凝胶。（2）进一步，通过引入具有AIE效应的四苯基乙烯基团，构筑新型荧光超分子聚合物水凝胶，为药物传递提供可视化的窗口。本项目的研究不仅有望拓展智能超分子水凝胶的构筑思路，同时也为新型形状记忆材料制备和药物传递体系的研究提供新的理论依据。

正交自组装是一种新的超分子自组装策略。项目围绕基于脲基嘧啶酮（UPy）的四重氢键，利用与四重氢键正交的π-π作用、金属配位作用和亲疏水作用等非共价作用力，协同驱动超分子自组装，构筑了一系列有趣的超分子组装体，实现了超分子聚合的定向可控和人工光捕获系统的高效开发。所开展工作包括如下方面：（1）对基于柱芳烃的凝胶（Tetrahedron Lett. 2018, 59, 1172-1182.）和对基于大环主客体作用的水凝胶进行了系统综述（J. Mater. Chem. B 2019, 7, 1526-1540.）；参与研究了基于柱芳烃主客体作用的水凝胶智能窗（Nature Commun. 2018, 9, 1737.）。（2）对基于UPy四重氢键的正交自组装进行了系统研究，包括与π-π作用的正交组装，构筑了形态规整的折叠结构（Org. Chem. Front. 2019, 6, 936-941.），研究了萘基桥连UPy的结构与组装的微观联系（Mater. Chem. Front. 2019, 3, 2738-2745.），研究了苯基桥连UPy的超分子聚合行为（Chin. J. Org. Chem. 2020, 40, 944-949.）；与金属配位作用正交组装调控超分子聚合过程（Chem. Commun. 2020, 56, 14385-14388.）、与主客体作用的正交组装新型超分子聚合物（Chin. J. Org. Chem. 2020, 40, 3847-3852.）。（3）开发了基于AIE型四重氢键超分子聚合物的光捕获系统（Chem. Commun. 2020, 56, 12021-12024.）。该光捕获系统不仅对理解自然界光合原理有促进作用，也在动态发光材料领域有着潜在的应用前景，尤其是通过简单调节给受体的比例可以发出白光。课题的开展不仅较好完成了项目预定的各项目标，同时也开拓了新的超分子水凝胶和正交自组装研究思路。