一种受珍珠层启发！ 基于石墨烯导电性纳米复合材料，用EMI屏蔽等

1成果简介

在工程应用中迫切需要实现高断裂韧性和优异导电性的结构纳米复合材料，以屏蔽电磁干扰（EMI）。然而，这仍然是一个重大挑战。

本文，浙江大学李鹏 研究员、许震 研究员等在《Chemical Engineering Journal》期刊

发表名为“Bidirectional shear-flow preparing lamellar graphene skeletons for tough and conductive nacre-like nanocomposites”的论文，研究受珍珠层“砖瓦”结构的启发，报道了一种由整齐的石墨烯片层骨架增强的类似珍珠层的环氧体纳米复合材料，该材料具有显著提高的断裂韧性和导电性。

通过双向剪切流场在膨胀挤压中有效地将氧化石墨烯片重新定向到高度排列，然后进行环境干燥和热还原，可以很容易地制备出整齐的片层状石墨烯骨架。在超低石墨烯负载为1.04 wt%的情况下，与纯环氧树脂相比，纳米复合材料的断裂韧性提高了3.84倍。电导率达到74.34 S/m，在8.2-12.4 GHz范围内具有出色的电磁干扰屏蔽效果（66.80 dB）。双向剪切流方法能够有效地制备具有高度恢复石墨烯晶格的有序层状石墨烯骨架，促进具有高韧性和导电性的纳米复合材料在具有EMI屏蔽性能的先进结构材料中的应用。

2图文导读

图1. Bidirectional shear-flow-assisted fabrication of LGAs and their nacre-like nanocomposites. a) Schematic illustration and corresponding photographs of the fabrication process. b) Schematic diagram and corresponding SEM images depicting the alignment evolution of GO sheets within the flow channel: (I) parallelly aligned GO nanosheets along the flow direction before entering the bidirectional shear-flow field; (II) gradual alignment under bidirectional shear-flow, and (III) long-range ordered lamellar structure. c) Optical image of the GO liquid crystalline texture observed in the bidirectional shear-flow channel under polarized light. d) Photographs of LGAs samples with various sizes. e) Radar plot comparing the EMI SE, fracture toughness, Young's modulus, flexural strength, and electrical conductivity of E-LGA20, E-LGA-S, and E-LGA20-iii.

图2. Structure of the lamellar skeletons and composites with different GO concentrations. a1-c1) Cross-sectional SEM images of LGA5, LGA10, and LGA20 skeletons, respectively. a2-c2) Cross-sectional SEM images of LGA5-iii, LGA10-iii, and LGA20-iii skeletons, respectively. a3-c3) Cross-sectional SEM images of E-LGA5-iii, E-LGA10-iii, and E-LGA20-iii, respectively. a4-c4) Statistical distribution of lamella spacing in the LGA skeletons.

图3. Fracture performance of E-LGAs. a) Force-displacement curves of epoxy, E-LGA20, E-LGA-S, E-LGA20-iii. b) KIC comparison of E-LGAs and epoxy. c) R curve of E-LGA-S and E-LGA20-iii. d) Comparison of KIC (Nanocomposite)/KIC (Epoxy) of the E-LGA20-iii with previously reported homogeneous epoxy nanocomposites.

图4. Crack paths and fracture mechanisms of E-LGAs and epoxy. a) SEM image of crack propagation in epoxy resin. b) SEM image of fracture surface of E-LGA20-iii. c, d) Enlarged SEM images of the regions highlighted by the blue and yellow boxes in b, respectively. Main fracture toughness mechanisms are indicated: crack branching (green arrows), crack deflection (yellow arrows), and interfacial friction (pink arrows).

图5. Electrical conductivity and EMI shielding performance of E-LGAs and Epoxy resin. a) Electrical conductivity of the E-LGAs and epoxy. b, c) Self-monitoring of structural integrity in E-LGA20-iii during the first and second loading cycles. d) EMI SET of E-LGAs and epoxy. e) Average SER, SEA, SET values of E-LGAs and epoxy in the X-band frequency range. f) Schematic illustration of the enhanced EMI shielding mechanism of E-LGAs.

3小结

总而言之，我们通过一种可扩展的双向剪切流策略，成功制备了一种受珍珠层启发的环氧纳米复合材料，其具有高度长程有序的层状石墨烯骨架。在石墨烯含量仅为1.04 wt%的超低载量下，所得纳米复合材料实现了1.55 MPa·m¹/²的断裂韧性（较纯环氧树脂提高了3.84倍）以及74.34 S/m的高电导率。这些性能提升归因于有效的外源性增韧机制以及沿层状结构形成的连续导电网络。此外，该复合材料在电磁干扰（EMI）屏蔽和可靠的裂纹自监测方面表现优异。本研究不仅验证了双向剪切流技术的有效性，还增强了其在可扩展生产具有定制结构骨架和集成多功能特性的宏观纳米复合材料方面的潜力。

文献：https://doi.org/10.1016/j.cej.2026.175349