Wang Chunyu, Gao Boyue, Fang Fuyi, Qi Wenhao, Yan Ge, Zhao Jun, Wang Wenbin, Bai Ruixue, Zhang Zhaoming, Zhang Zhitao, Zhang Wenming, Yan Xuzhou
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
School of Chemistry and Chemical Engineering, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 201203, P. R. China.
Angew Chem Int Ed Engl. 2024 Jul 8;63(28):e202404481. doi: 10.1002/anie.202404481. Epub 2024 Jun 12.
The pursuit of fabricating high-performance graphene films has aroused considerable attention due to their potential for practical applications. However, developing both stretchable and tough graphene films remains a formidable challenge. To address this issue, we herein introduce mechanical bond to comprehensively improve the mechanical properties of graphene films, utilizing [2]rotaxane as the bridging unit. Under external force, the [2]rotaxane cross-link undergoes intramolecular motion, releasing hidden chain and increasing the interlayer slip distance between graphene nanosheets. Compared with graphene films without [2]rotaxane cross-linking, the presence of mechanical bond not only boosted the strength of graphene films (247.3 vs 74.8 MPa) but also markedly promoted the tensile strain (23.6 vs 10.2 %) and toughness (23.9 vs 4.0 MJ/m). Notably, the achieved tensile strain sets a record high and the toughness surpasses most reported results, rendering the graphene films suitable for applications as flexible electrodes. Even when the films were stretched within a 20 % strain and repeatedly bent vertically, the light-emitting diodes maintained an on-state with little changes in brightness. Additionally, the film electrodes effectively actuated mechanical joints, enabling uninterrupted grasping movements. Therefore, the study holds promise for expanding the application of graphene films and simultaneously inspiring the development of other high-performance two-dimensional films.
由于其在实际应用中的潜力，制备高性能石墨烯薄膜的研究引起了广泛关注。然而，开发兼具可拉伸性和韧性的石墨烯薄膜仍然是一项艰巨的挑战。为了解决这个问题，我们在此引入机械键，以[2]轮烷作为桥连单元，全面改善石墨烯薄膜的力学性能。在外力作用下，[2]轮烷交联发生分子内运动，释放隐藏链并增加石墨烯纳米片之间的层间滑移距离。与未进行[2]轮烷交联的石墨烯薄膜相比，机械键的存在不仅提高了石墨烯薄膜的强度（247.3对74.8 MPa），还显著提高了拉伸应变（23.6对10.2 %）和韧性（23.9对4.0 MJ/m）。值得注意的是，所实现的拉伸应变创下了新高，韧性超过了大多数已报道的结果，使得石墨烯薄膜适用于作为柔性电极。即使薄膜在20 %的应变范围内拉伸并反复垂直弯曲，发光二极管仍保持导通状态，亮度变化很小。此外，薄膜电极有效地驱动机械关节，实现不间断的抓取动作。因此，这项研究有望扩大石墨烯薄膜的应用范围，同时激发其他高性能二维薄膜的发展。
