An Liu#, Hua Qiu#, Xinghan Lu, Hua Guo, Jinwen Hu, Chaobo Liang, Mukun He, Ze Yu, Yali Zhang*, Jie Kong and Junwei Gu*. Asymmetric Structural MXene/PBO Aerogels for High-Performance Electromagnetic Interference Shielding with Ultra-Low Reflection. Advanced Materials, 2024, 10.1002/adma.202414085. 2023IF=27.4
https://onlinelibrary.wiley.com/doi/10.1002/adma.202414085
Abstract
Electromagnetic interference (EMI) shielding materials with low electromagnetic (EM) waves reflection characteristics are ideal materials for blocking EM radiation and pollution. Materials with low reflectivity must be constructed using materials with excellent EM waves absorption properties. However, materials simultaneously possessing both low reflectivity and excellent EMI shielding performance remain scarce, consequently, multilayer structures need to be developed. Poly(p-phenylene–2,6–benzobisoxazole) nanofibers (PNF) are prepared by deprotonation. PNF are combined with MXene and heterostructure MXene@Ni prepared by in-situ growth; MXene@Ni/PNF acts as an EM absorption layer while the MXene/PNF acts as an EM reflective layer. Finally, (MXene@Ni/PNF)–(MXene/PNF) aerogels are prepared by layer-by-layer freeze-drying based on the layered modular design concept. Experimental characterizations revealed that (MXene@Ni/PNF)–(MXene/PNF) aerogels enable the efficient absorption-reflection-reabsorption of EM waves, effectively eliminating EMI. When the mass ratio of MXene to Ni in MXene@Ni is 1:6 and the mass fraction of MXene in the reflective layer is 80 wt%, the (MXene@Ni/PNF)–(MXene/PNF) aerogels exhibit excellent EMI shielding performance (71 dB) and a very low reflection coefficient (R = 0.10). Finite element simulations verified that the developed asymmetric structural aerogels achieve high EMI shielding performance with low reflection characteristics. In addition, (MXene@Ni/PNF)–(MXene/PNF) aerogels display excellent infrared camouflage ability.
具有低反射特性的電磁屏蔽材料是防止電磁輻射和電磁污染的理想材料，要想實現電磁屏蔽材料的低反射特性，需要引入吸收層使材料具有優異的電磁波吸收性能。但是如何合理地設計吸收層與反射層，并將兩者實現高效的集成是一個亟需解決的問題。本文采用去質子化法制備聚對苯撐苯并二噁唑納米纖維（PNF），借助原位生長法、通過“靜電吸附-溶劑熱還原”制備異質結構MXene@Ni電磁功能填料，以PNF為基體，MXene與MXene@Ni為填料，基于分層模塊設計理念，經逐層冷凍干燥技術制備(MXene@Ni/PNF)-(MXene/PNF)氣凝膠。得益于吸收層MXene@Ni/PNF與反射層MXene/PNF的協同作用，實現了(MXene@Ni/PNF)-(MXene/PNF)氣凝膠對入射電磁波的“吸收-反射-再吸收”過程。當MXene@Ni中MXene與Ni的質量比為1:6、反射層MXene/PNF中MXene質量分數為80 wt%時，該氣凝膠在X波段具有優異的電磁屏蔽性能（71 dB）和極低的平均反射系數（0.10）。有限元模擬進一步驗證了該氣凝膠具有優異的電磁屏蔽性能和低反射特性。此外，(MXene@Ni/PNF)-(MXene/PNF)氣凝膠還具有紅外偽裝的功能。
論文亮點
1. 借助原位生長法、通過“靜電吸附-溶劑熱還原”在MXene表面原位生長海膽狀的磁性Ni納米顆粒，制備異質結構MXene@Ni電磁功能填料。當MXene與Ni質量比為1:6時，MXene@Ni復合材料在2~3 mm厚度范圍內具有良好的阻抗匹配特性（|Zin/Z0|的值更接近于1）。
2. 以聚對苯撐苯并二噁唑納米纖維（PNF）為基體，MXene與MXene@Ni為填料，基于分層模塊設計理念，經逐層冷凍干燥技術制備(MXene@Ni/PNF)-(MXene/PNF)氣凝膠。當MXene@Ni中MXene與Ni的質量比為1:6、反射層MXene/PNF中MXene質量分數為80 wt%時，該氣凝膠在X波段具有優異的電磁屏蔽性能（71 dB）和極低的平均反射系數（0.10）。
3. 由于MXene的低紅外發射率（24.6%）和氣凝膠的優異隔熱性能（吸收層MXene@Ni/PNF導熱系數為0.092 W/(m·K)；反射層MXene/PNF導熱系數為0.069 W/(m·K)），(MXene@Ni/PNF)-(MXene/PNF)氣凝膠具有優異的紅外偽裝特性。
第一作者：柳岸、邱華
郵件地址：liuan2000@mail.nwpu.edu.cn、huaqiu@nwpu.edu.cn
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