Sui Bowen, Zhu Youliang, Jiang Xuemei, Wang Yifan, Zhang Niboqia, Lu Zhongyuan, Yang Bai, Li Yunfeng
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, China.
Nat Commun. 2023 Oct 25;14(1):6782. doi: 10.1038/s41467-023-42516-8.
Assembly of nanoparticles into macroscopic materials with mechanical robustness, green processability, and recastable ability is an important and challenging task in materials science and nanotechnology. As an emerging nanoparticle with superior properties, macroscopic materials assembled from carbon dots will inherit their properties and further offer collective properties; however, macroscopic materials assembled from carbon dots solely remain unexplored. Here we report macroscopic films assembled from carbon dots modified by ureido pyrimidinone. These films show tunable fluorescence inherited from carbon dots. More importantly, these films exhibit collective properties including self-healing, re-castability, and superior mechanical properties, with Young's modulus over 490 MPa and breaking strength over 30 MPa. The macroscopic films maintain original mechanical properties after several cycles of recasting. Through scratch healing and welding experiments, these films show good self-healing properties under mild conditions. Moreover, the molecular dynamics simulation reveals that the interplay of interparticle and intraparticle hydrogen bonding controls mechanical properties of macroscopic films. Notably, these films are processed into diverse shapes by an eco-friendly hydrosetting method. The methodology and results in this work shed light on the exploration of functional macroscopic materials assembled from nanoparticles and will accelerate innovative developments of nanomaterials in practical applications.
将纳米颗粒组装成具有机械强度、绿色可加工性和可重塑能力的宏观材料是材料科学和纳米技术中一项重要且具有挑战性的任务。作为一种具有优异性能的新兴纳米颗粒，由碳点组装而成的宏观材料将继承其特性并进一步展现集体性质；然而，仅由碳点组装而成的宏观材料仍未得到探索。在此，我们报道了由脲嘧啶酮修饰的碳点组装而成的宏观薄膜。这些薄膜展现出从碳点继承而来的可调谐荧光。更重要的是，这些薄膜具有包括自愈性、可重塑性和优异机械性能在内的集体性质，杨氏模量超过490兆帕，断裂强度超过30兆帕。经过多次重塑循环后，宏观薄膜仍保持原始机械性能。通过划痕修复和焊接实验，这些薄膜在温和条件下表现出良好的自愈性能。此外，分子动力学模拟表明，颗粒间和颗粒内氢键的相互作用控制着宏观薄膜的机械性能。值得注意的是，这些薄膜通过一种环保的水固化方法被加工成各种形状。这项工作中的方法和结果为探索由纳米颗粒组装而成的功能性宏观材料提供了思路，并将加速纳米材料在实际应用中的创新发展。
