Zhang Si-Chao, Hou YuanZhen, Chen Si-Ming, He Zhen, Wang Ze-Yu, Zhu YinBo, Wu HengAn, Gao Huai-Ling, Yu Shu-Hong
Department of Chemistry, New Cornerstone Science Laboratory, Institute of Biomimetic Materials and Chemistry, Anhui Engineering Laboratory of Biomimetic Materials, Division of Nanomaterials and Chemistry, Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China.
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, 230027, China.
Adv Mater. 2024 Aug;36(35):e2405682. doi: 10.1002/adma.202405682. Epub 2024 Jul 2.
Assembling ultrathin nanosheets into layered structure represents one promising way to fabricate high-performance nanocomposites. However, how to minimize the internal defects of the layered assemblies to fully exploit the intrinsic mechanical superiority of nanosheets remains challenging. Here, a dual-scale spatially confined strategy for the co-assembly of ultrathin nanosheets with different aspect ratios into a near-perfect layered structure is developed. Large-aspect-ratio (LAR) nanosheets are aligned due to the microscale confined space of a flat microfluidic channel, small-aspect-ratio (SAR) nanosheets are aligned due to the nanoscale confined space between adjacent LAR nanosheets. During this co-assembly process, SAR nanosheets can flatten LAR nanosheets, thus reducing wrinkles and pores of the assemblies. Benefiting from the precise alignment (orientation degree of 90.74%) of different-sized nanosheets, efficient stress transfer between nanosheets and interlayer matrix is achieved, resulting in layered nanocomposites with multiscale mechanical enhancement and superior fatigue durability (100 000 bending cycles). The proposed co-assembly strategy can be used to orderly integrate high-quality nanosheets with different sizes or diverse functions toward high-performance or multifunctional nanocomposites.
将超薄纳米片组装成层状结构是制备高性能纳米复合材料的一种有前景的方法。然而，如何最小化层状组装体的内部缺陷以充分发挥纳米片的固有机械优势仍然具有挑战性。在此，开发了一种双尺度空间限制策略，用于将不同纵横比的超薄纳米片共组装成近乎完美的层状结构。大纵横比（LAR）纳米片由于扁平微流体通道的微尺度限制空间而排列，小纵横比（SAR）纳米片由于相邻LAR纳米片之间的纳米尺度限制空间而排列。在这种共组装过程中，SAR纳米片可以使LAR纳米片变平，从而减少组装体的皱纹和孔隙。受益于不同尺寸纳米片的精确排列（取向度为90.74%），实现了纳米片与层间基体之间的有效应力传递，从而得到具有多尺度机械增强和优异疲劳耐久性（100000次弯曲循环）的层状纳米复合材料。所提出的松组装策略可用于将不同尺寸或多种功能的高质量纳米片有序集成，以制备高性能或多功能纳米复合材料。
