Xiong Jiaofeng, Wang Xiaowei, Li Lingling, Li Qingning, Zheng Sijie, Liu Ziyang, Li Weizheng, Yan Feng
Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Suzhou Key Laboratory of Soft Material and New Energy, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
Angew Chem Int Ed Engl. 2024 Jan 2;63(1):e202316375. doi: 10.1002/anie.202316375. Epub 2023 Nov 30.
Service life and range of polymer materials is heavily reliant on their elasticity and mechanical stability under long-term loading. Slippage of chain segments under load leads to significant hysteresis of the hydrogels, limiting its repeatability and mechanical stability. Achieving the desired elasticity exceeding that of rubber is a great challenge for hydrogels, particularly when subjected to large deformations. Here, low-hysteresis and high-toughness hydrogels were developed through controllable interactions of porous cationic polymers (PCPs) with adjustable counteranions, including reversible bonding of PCP frameworks/polymer segments (polyacrylamide, PAAm) and counteranions/PAAm. This strategy reduces chain segment slippage under load, endowing the PCP-based hydrogels (PCP-gels) with good elasticity under large deformations (7 % hysteresis at a strain ratio of 40). Furthermore, due to the enlarged chain segments entanglement by PCP, the PCP-gels exhibit large strain (13000 %), significantly enhanced toughness (68 MJ m ), high fracture energy (43.1 kJ m ), and fatigue resistance. The unique properties of these elastic PCP-gels have promising applications in the field of flexible sensors.
聚合物材料的使用寿命和范围在很大程度上依赖于它们在长期负载下的弹性和机械稳定性。负载下链段的滑动会导致水凝胶出现显著的滞后现象，限制其可重复性和机械稳定性。对于水凝胶来说，实现超过橡胶的理想弹性是一项巨大的挑战，尤其是在承受大变形时。在此，通过多孔阳离子聚合物（PCP）与可调节抗衡离子的可控相互作用，开发出了低滞后和高韧性的水凝胶，包括PCP骨架/聚合物链段（聚丙烯酰胺，PAAm）与抗衡离子/PAAm之间的可逆键合。这种策略减少了负载下链段的滑动，使基于PCP的水凝胶（PCP凝胶）在大变形下具有良好的弹性（在应变比为40时滞后率为7%）。此外，由于PCP使链段缠结增大，PCP凝胶表现出大应变（13000%）、显著增强的韧性（68 MJ m）、高断裂能（43.1 kJ m）和抗疲劳性。这些弹性PCP凝胶的独特性能在柔性传感器领域具有广阔的应用前景。
