Mechanically Interlocked Polyrotaxane Networks with Collective Motions of Multiple Main‐Chain Mechanical Bonds

• Published in: Angewandte Chemie International Edition 2024-10, Vol.63 (43), p.e202410834-n/a
• Main Authors: Yang, Li, Wang, Yuanhao, Liu, Guoquan, Zhao, Jun, Cheng, Lin, Zhang, Zhaoming, Bai, Ruixue, Liu, Yuhang, Yang, Mengling, Yu, Wei, Yan, Xuzhou
• Format: Article
• Language: English
• Subjects: Chemical bonds; Dynamic characteristics; dynamic materials; host–guest systems; main-chain polyrotaxanes; mechanical bonds; Mechanical properties; mechanically interlocked polymers; Molecular dynamics; Polymers; Rheological properties; Rotaxanes; Shafts (machine elements); Stretchability; Tensile tests
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202410834

Type I main‐chain polyrotaxanes (PRs) with multiple wheels threaded onto the axle are widely employed to design slide‐ring materials. However, Type II main‐chain PRs with axles threading into the macrocycles on the polymer backbones have rarely been studied, although they feature special topological structures and dynamic characteristics. Herein, we report the design and preparation of Type II main‐chain PR‐based mechanically interlocked networks (PRMINs), based on which the relationship between microscopic motion of mechanical bonds on the PRs and macroscopic mechanical performance of materials has been revealed. The representative PRMIN‐2 exhibits a robust feature in tensile tests with high stretchability (1680 %) and toughness (47.5 MJ/m3). Moreover, it also has good puncture performance with puncture energy of 22.0 mJ. Detailed rheological measurements and coarse‐grained molecular dynamics (CGMD) simulation reveal that the embedded multiple [2]rotaxane mechanical bonds on the PR backbones of PRMINs could undergo a synergistic long‐range sliding motion under external force, with the introduction of collective dangling chains into the network. As a result, the synchronized motions of coherent PR chains can be readily activated to accommodate network deformation and efficiently dissipate energy, thereby leading to enhanced mechanical performances of PRMINs. The relationship between the microscopic collective motion of mechanical bonds in Type‐II main‐chain polyrotaxane (PR) backbones and the macroscopic mechanical performance of the resulting PR‐based mechanically interlocked networks (PRMINs) have been investigated. The synchronized motions of coherent PR chains can be readily activated to accommodate network deformation and efficiently dissipate energy, thereby leading to enhanced mechanical performances of the PRMINs.