Electromagnetic interference (EMI) shielding materials with low reflection and excellent microwave absorption characteristics are highly desirable for high-speed electronics devices to attenuate radiated emissions. Herein, we developed a highly absorption dominated composite EMI shielding foams with “honeycomb” structure through chemical foaming and subsequent in situ vapor deposition of polypyrrole (PPy) within polyimide (PI) foams. After the deposition of PPy, the obtained porous PI foams exhibit electrical conductivity of 2.7 × 10 S/m. In addition, the composite foams demonstrate the highest absorption coefficient of 0.8 and EMI shielding efficiency of 41.1 dB with a thickness of 8 mm. Moreover, the optimal reflection loss (RL) of the composite PI/FeO-20@PPy foam (PF/FeO-20@PPy) reach up to −31 dB at 6.0 mm and ≤ −10 dB in the whole X band with a thickness of ≥4 mm. Moreover, the 3D porous structure of PI foam and favorable electrical conductivity of in-situ formed PPy film can contribute to the high sensing performance of PI@PPy foam (PF@PPy). This study provides a novel strategy for the development of lightweight, EMI shielding and microwave absorption materials for advanced applications in flexible anti-radiation and stealth devices.

中文翻译：

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用于电磁波屏蔽的蜂窝状聚酰亚胺/Fe3O4@PPy泡沫具有优异的吸收特性

具有低反射和优异微波吸收特性的电磁干扰（EMI）屏蔽材料对于高速电子设备来说是非常理想的，可以衰减辐射发射。在此，我们通过化学发泡和随后在聚酰亚胺（PI）泡沫中原位气相沉积聚吡咯（PPy），开发了一种具有“蜂窝”结构的高吸收主导复合EMI屏蔽泡沫。沉积PPy后，所得多孔PI泡沫的电导率为2.7×10 S/m。此外，复合泡沫在厚度为8毫米时表现出最高的吸收系数为0.8，EMI屏蔽效率为41.1 dB。此外，复合PI/FeO-20@PPy泡沫（PF/FeO-20@PPy）的最佳反射损耗（RL）在6.0 mm处达到-31 dB，在整个X波段内达到≤-10 dB，厚度≥4毫米。此外，PI泡沫的3D多孔结构和原位形成的PPy薄膜良好的导电性有助于PI@PPy泡沫（PF@PPy）的高传感性能。这项研究为开发轻质、EMI 屏蔽和微波吸收材料以用于柔性抗辐射和隐形设备的高级应用提供了一种新颖的策略。