Facile mechanochemical cycloreversion of polymer cross-linkers enhances tear resistance

• 成果类型: Article
• 署名作者: Wang, Shu; Hu, Yixin; Kouznetsova, Tatiana B.; Sapir, Liel; Chen, Danyang; Herzog-Arbeitman, Abraham; Johnson, Jeremiah A.; Rubinstein, Michael; Craig, Stephen L.
• 署名单位: Duke University; Duke University; Duke University; Duke University; Duke University; Hokkaido University; Massachusetts Institute of Technology (MIT)
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-14102
• DOI: 10.1126/science.adg3229
• 发表日期: 2023-06-01
• 页码: 1248-1252
• 关键词: mechanical performance; FORCE; DYNAMICS; fracture; fatigue; spectroscopy; elasticity; hydrogels; strength; BEHAVIOR

摘要

The mechanical properties of covalent polymer networks often arise from the permanent end-linking or cross-linking of polymer strands, and molecular linkers that break more easily would likely produce materials that require less energy to tear. We report that cyclobutane-based mechanophore cross-linkers that break through force-triggered cycloreversion lead to networks that are up to nine times as tough as conventional analogs. The response is attributed to a combination of long, strong primary polymer strands and cross-linker scission forces that are approximately fivefold smaller than control cross-linkers at the same timescales. The enhanced toughness comes without the hysteresis associated with noncovalent cross-linking, and it is observed in two different acrylate elastomers, in fatigue as well as constant displacement rate tension, and in a gel as well as elastomers.