Elastic films of single-crystal two-dimensional covalent organic frameworks

• 成果类型: Article
• 署名作者: Yang, Yonghang; Liang, Baokun; Kreie, Jakob; Hambsch, Mike; Liang, Zihao; Wang, Cheng; Huang, Senhe; Dong, Xin; Gong, Li; Liang, Chaolun; Lou, Dongyang; Zhou, Zhipeng; Lu, Jiaxing; Yang, Yang; Zhuang, Xiaodong; Qi, Haoyuan; Kaiser, Ute; Mannsfeld, Stefan C. B.; Liu, Wei; Goelzhaeuser, Armin; Zheng, Zhikun
• 署名单位: Sun Yat Sen University; Sun Yat Sen University; Guangdong University of Technology; Ulm University; University of Bielefeld; Technische Universitat Dresden; Technische Universitat Dresden; Shanghai Jiao Tong University; Sun Yat Sen University; Southern Marine Science & Engineering Guangdong Laboratory; Southern Marine Science & Engineering Guangdong Laboratory (Guangzhou)
• 刊物名称: Nature
• ISSN/ISSBN: 0028-5057
• DOI: 10.1038/s41586-024-07505-x
• 发表日期: 2024-06-27
• 关键词: thin-films; strength; polymer

摘要

The properties of polycrystalline materials are often dominated by defects; two-dimensional (2D) crystals can even be divided and disrupted by a line defect1-3. However, 2D crystals are often required to be processed into films, which are inevitably polycrystalline and contain numerous grain boundaries, and therefore are brittle and fragile, hindering application in flexible electronics, optoelectronics and separation1-4. Moreover, similar to glass, wood and plastics, they suffer from trade-off effects between mechanical strength and toughness5,6. Here we report a method to produce highly strong, tough and elastic films of an emerging class of 2D crystals: 2D covalent organic frameworks (COFs) composed of single-crystal domains connected by an interwoven grain boundary on water surface using an aliphatic bi-amine as a sacrificial go-between. Films of two 2D COFs have been demonstrated, which show Young's moduli and breaking strengths of 56.7 +/- 7.4 GPa and 73.4 +/- 11.6 GPa, and 82.2 +/- 9.1 N m-1 and 29.5 +/- 7.2 N m-1, respectively. We predict that the sacrificial go-between guided synthesis method and the interwoven grain boundary will inspire grain boundary engineering of various polycrystalline materials, endowing them with new properties, enhancing their current applications and paving the way for new applications. A method is reported that produces highly strong, tough and elastic 2D COF films, using a sacrificial go-between, which endows them with new properties, enhances their current applications and paves the way for new applications.