Zhao Zehao, Zhang Limin, Wu Hongjing
MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, Northwestern Polytechnical University, Xi'an, 710072, P. R. China.
Adv Mater. 2022 Oct;34(43):e2205376. doi: 10.1002/adma.202205376. Epub 2022 Sep 28.
Demand for electromagnetic wave (EMW) absorbers continues to increase with technological advances in wearable electronics and military applications. In this study, a new strategy to overcome the drawbacks of current absorbers by employing the co-contribution of functional polymer frameworks and liquids with strong EMW absorption properties is proposed. Strongly polar water, dimethyl sulfoxide/water mixtures, and highly conductive 1-ethyl-3-methylimidazolium ethyl sulfate ([EMI][ES]) are immobilized in dielectrically inert polymer networks to form different classes of gels (hydrogels, organogels, and ionogels). These gels demonstrate a high correlation between their dielectric properties and polarity/ionic conductivity/non-covalent interaction of immobilized liquids. Thus, the EMW absorption performances of the gels can be precisely tuned over a wide range due to the diversity and stability of the liquids. The prepared hydrogels show good shielding performance (shielding efficiency > 20 dB) due to the high dielectric constants, while organogels with moderate attenuation ability and impedance matching achieve full-wave absorption in X-band (8.2-12.4 GHz) at 2.5 ± 0.5 mm. The ionogels also offer a wide effective absorption bandwidth (10.79-16.38 GHz at 2.2 mm) via prominent ionic conduction loss. In short, this work provides a conceptually novel platform to develop high-efficient, customizable, and low-cost functional absorbers.
随着可穿戴电子设备和军事应用技术的进步，对电磁波（EMW）吸收剂的需求持续增长。在本研究中，提出了一种新策略，即通过利用具有强EMW吸收特性的功能聚合物框架和液体的共同作用来克服当前吸收剂的缺点。将强极性水、二甲基亚砜/水混合物和高导电性的1-乙基-3-甲基咪唑鎓乙基硫酸盐（[EMI][ES]）固定在介电惰性的聚合物网络中，以形成不同类型的凝胶（水凝胶、有机凝胶和离子凝胶）。这些凝胶在其介电性能与固定化液体的极性/离子电导率/非共价相互作用之间表现出高度相关性。因此，由于液体的多样性和稳定性，凝胶的EMW吸收性能可以在很宽的范围内进行精确调节。所制备的水凝胶由于具有高介电常数而表现出良好的屏蔽性能（屏蔽效率>20 dB），而具有适度衰减能力和阻抗匹配的有机凝胶在2.5±0.5 mm厚度时在X波段（8.2 - 12.4 GHz）实现全波吸收。离子凝胶通过显著的离子传导损耗也提供了较宽的有效吸收带宽（在2.2 mm厚度时为10.79 - 16.38 GHz）。简而言之，这项工作为开发高效、可定制且低成本的功能吸收剂提供了一个概念上新颖的平台。
