Nanoconfined polymerization limits crack propagation in hysteresis-free gels

Weizheng Li¹, Xiaoliang Wang², Ziyang Liu¹, Xiuyang Zou¹, Zhihao Shen³, Dong Liu³, Lingling Li¹, Yu Guo¹, Feng Yan^1,4*（严锋） 

¹Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Negative Carbon Technologies College of Chemistry, Suzhou Key Laboratory of Soft Material and New Energy, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China.

²School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.

³Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.

⁴State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, China

Nature Materials, 2024, 23, 131–138.

Abstract: Consecutive mechanical loading cycles cause irreversible fatigue damage and residual strain in gels, affecting their service life and application scope. Hysteresis-free hydrogels within a limited deformation range have been created by various strategies. However, large deformation and high elasticity are inherently contradictory attributes. Here we present a nanoconfined polymerization strategy for producing tough and near-zero-hysteresis gels under a large range of deformations. Gels are prepared through in situ polymerization within nanochannels of covalent organic frameworks or molecular sieves. The nanochannel confinement and strong hydrogen bonding interactions with polymer segments are crucial for achieving rapid self-reinforcement. The rigid nanostructures relieve the stress concentration at the crack tips and prevent crack propagation, enhancing the ultimate fracture strain (17,580 ± 308%), toughness (87.7 ± 2.3 MJ m⁻³) and crack propagation strain (5,800%) of the gels. This approach provides a general strategy for synthesizing gels that overcome the traditional trade-offs of large deformation and high elasticity.

链接： https://www.nature.com/articles/s41563-023-01697-9