School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
Nat Commun. 2022 Nov 4;13(1):6654. doi: 10.1038/s41467-022-34286-6.
Integrating individual microscopic motion to perform tasks in macroscopic sale is common in living organisms. However, developing artificial materials in which molecular-level motions could be amplified to behave macroscopically is still challenging. Herein, we present a class of mechanically interlocked networks (MINs) carrying densely rotaxanated backbones as a model system to understand macroscopic mechanical properties stemmed from the integration and amplification of intramolecular motion of the embedded [2]rotaxane motifs. On the one hand, the motion of mechanical bonds introduces the original dangling chains into the network, and the synergy of numerous such microscopic motions leads to an expansion of entire network, imparting good stretchability and puncture resistance to the MINs. On the other hand, the dissociation of host-guest recognition and subsequent sliding motion represent a peculiar energy dissipation pathway, whose integration and amplification result in the bulk materials with favorable toughness and damping capacity. Thereinto, we develop a continuous stress-relaxation method to elucidate the microscopic motion of [2]rotaxane units, which contributes to the understanding of the relationship between cumulative microscopic motions and amplified macroscopic mechanical performance.
在宏观尺度上执行任务时整合个体微观运动在生物活体中很常见。然而，开发能够放大分子级运动以表现出宏观行为的人工材料仍然具有挑战性。在此，我们提出了一类带有密集轮烷骨架的机械互锁网络（MINs）作为模型体系，以了解源于嵌入的[2]轮烷结构单元的分子内运动的整合和放大的宏观机械性能。一方面，机械键的运动将原始的悬空链引入网络中，众多此类微观运动的协同作用导致整个网络的扩展，赋予 MINs 良好的拉伸性和抗刺穿性。另一方面，主体-客体识别的解缔合及其随后的滑动运动代表了一种特殊的能量耗散途径，其整合和放大导致具有良好韧性和阻尼能力的块状材料。其中，我们开发了一种连续的应力松弛方法来阐明[2]轮烷单元的微观运动，这有助于理解累积微观运动与放大的宏观机械性能之间的关系。
