Liu Zhi, Song Meiping, Liang Weiqi, Gao Xueping, Zhu Bo
Key Laboratory for Liquid Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China.
Carbon Fiber Engineering Research Center, Shandong University, Jinan 250061, China.
Materials (Basel). 2024 Jun 6;17(11):2767. doi: 10.3390/ma17112767.
Flexible paper-based materials play a crucial role in the field of flexible electromagnetic shielding due to their thinness and controllable shape. In this study, we employed the wet paper forming technique to prepare carbon fiber paper with a thickness gradient. The electromagnetic shielding performance of the carbon fiber paper varies with the ladder-like thickness distribution. Specifically, an increase in thickness gradient leads to higher reflectance of the carbon fiber paper. Within the X-band frequency range (8.2-12.4 GHz), reflectivity decreases as electromagnetic wave frequency increases, indicating enhanced penetration of electromagnetic waves into the interior of the carbon fiber paper. This enhancement is attributed to an increased fiber content per unit area resulting from a greater thickness gradient, which further enhances reflection loss and promotes internal multiple reflections and scattering effects, leading to increased absorption loss. Notably, at a 5 mm thickness, our carbon fiber paper exhibits an impressive average overall shielding performance, reaching 63.46 dB. Moreover, it exhibits notable air permeability and mechanical properties, thereby assuming a pivotal role in the realm of flexible wearable devices in the foreseeable future.
柔性纸质材料因其薄度和可控制的形状在柔性电磁屏蔽领域发挥着关键作用。在本研究中，我们采用湿纸成型技术制备了具有厚度梯度的碳纤维纸。碳纤维纸的电磁屏蔽性能随阶梯状厚度分布而变化。具体而言，厚度梯度的增加导致碳纤维纸的反射率更高。在X波段频率范围（8.2 - 12.4 GHz）内，反射率随着电磁波频率的增加而降低，这表明电磁波向碳纤维纸内部的穿透增强。这种增强归因于更大的厚度梯度导致单位面积内纤维含量增加，这进一步增强了反射损耗并促进了内部多次反射和散射效应，从而导致吸收损耗增加。值得注意的是，在5毫米厚度时，我们的碳纤维纸展现出令人印象深刻的平均总体屏蔽性能，达到63.46分贝。此外，它还具有显著的透气性和机械性能，因此在可预见的未来在柔性可穿戴设备领域将发挥关键作用。
