作者：Xiaofeng Hu, Yali Zhang, Hua Guo, Mukun He, Hua Qiu, Xuetao Shi, Lei Wang*, Junwei Gu*
关键字：electromagnetic interference shielding, flexibility, heterogeneous structure, infrared camouflage, low reflection
论文来源：期刊
发表时间：2025年

Xiaofeng Hu, Yali Zhang, Hua Guo, Mukun He, Hua Qiu, Xuetao Shi, Lei Wang*, Junwei Gu*. Multifunctional Flexible WPU Composite Aerogels with Sandwich Structure for Dual-Sided Low-Reflection Electromagnetic Interference Shielding, Advanced Functional Materials, 2025, 10.1002/adfm.202517665. 2024IF=19.0. （1区材料科学Top期刊）

Abstract

With the increasingly severe electromagnetic pollution, the demand for low-reflection electromagnetic interference shielding (EMI) materials has become progressively urgent. Based on the layered design, the (MXene@CoFe₂O₄/waterborne polyurethane (WPU))-(MXene/WPU)-(MXene@CoFe₂O₄/WPU) composite aerogels with sandwich structure (SWCA) are prepared by layer freezing and freeze-drying method, using WPU as the matrix and heterostructure MXene@CoFe₂O₄ prepared by solvothermal reduction as electromagnetic filler. When the mass ratio of MXene to CoFe₂O₄ is 1:6, MXene@CoFe₂O₄ exhibits optimal impedance matching (with the value of |Z_in/Z₀| closer to 1). Due to the synergistic effect between the absorbing layer of MXene@CoFe₂O₄/WPU aerogels and the reflecting layer of MXene/WPU aerogels, SWCA assembled with 80 wt.% MXene/WPU aerogels and 40 wt.% MXene@CoFe₂O₄-3/WPU aerogels achieve high EMI shielding effectiveness (77 dB) and low reflection (0.14) in the X band. Besides, SWCA demonstrates dual-sided low-reflection EMI shielding performance, to the extent that in practical applications, they are no longer restricted to specific installation directions. Moreover, SWCA shows high compressive stress (maximum compressive stress of 264.0 kPa at 50% compressive strain), compressive resilience (88% resilience after 100 cycles of compression), excellent thermal insulation (thermal conductivity between 0.0843 and 0.0941 W·(m·K)^-1) and infrared camouflage performance. The multifunctional flexible EMI shielding aerogels with low reflection and high performance holds great promise for application prospect in next-generation electronic devices.

随着电磁污染日益严峻，开发具有低反射特性的电磁屏蔽（EMI）复合材料的需求日趋迫切。本文基于分层模块设计理念，以水性聚氨酯（WPU）为基体，溶剂热法制备的异质结构MXene@CoFe2O4为功能填料，经逐层冷冻干燥技术制备三明治结构(MXene@CoFe₂O₄/WPU)-(MXene/WPU)-(MXene@CoFe₂O₄/WPU)气凝胶（SWCA）。当MXene@CoFe₂O₄中MXene与CoFe₂O₄质量比为1：6（MXene@CoFe₂O₄-3）时，MXene@CoFe₂O₄具有良好的阻抗匹配特性（|Zin/Z0|的值更接近于1）。得益于吸收层MXene@CoFe₂O₄/WPU气凝胶与反射层MXene/WPU气凝胶的协同作用，当MXene@CoFe₂O₄-3/WPU气凝胶中MXene@CoFe₂O₄-3质量分数为40 wt%、MXene/WPU气凝胶中MXene质量分数为80 wt%时，SWCA诱导入射电磁波经历“吸收-反射-再吸收”过程，在X波段的电磁屏蔽性能可达77 dB，平均反射系数仅为0.14。该气凝胶更突破性地展现出双面低反射EMI屏蔽性能，在实际应用中无需受限于特定安装方向。此外，SWCA还兼具高压缩应力（50%压缩应变下的最大压应力为264.0 kPa）、压缩回弹特性（循环压缩100次气凝胶的回弹率达88%）、优异隔热性能（导热系数处于0.0843-0.0941 W/(m·K)之间）以及红外伪装的功能。这种兼具低反射、高性能、多功能的柔性电磁屏蔽气凝胶在下一代电子器件中具有广阔的应用前景。