Programmable Electromagnetic Switching in Shape‐Memory‐Driven Liquid Metal/Polyimide/Aramid Nanofiber Aerogels for Intelligent Wave Management
Shunan Wang, Zhenyu Cheng, Yi Yan, Junru Yao, Yijie Liu, Jiaqi Tao, Lvtong Duan, Yanling Weng, Hongbao Zhu, Haiyan Zhuang, Jintang Zhou, Xiuqing Hao
Abstract
Abstract Developing intelligent advanced materials with switchable electromagnetic (EM) absorption and shielding functions is one of the cutting‐edge challenges in EM stealth and information protection. However, the wave‐absorbing function relies on the effective loss of EM waves, while the shielding function relies on reflection and blocking of EM waves, which rely on different mechanisms, making it difficult to balance compatibility and tunability. Here, a shape memory‐driven liquid metal/polyimide/aramid nanofiber (LPA) composite aerogel with programmable EM switching is developed, which breaks through the technical bottleneck of traditional EM materials with a single function and is difficult to integrate. The material realizes the continuous modulation of conductivity through compressive strain‐driven porous structure reconstruction and liquid metal (LM) network reorganization, thus switching from polarization loss‐dominated EM absorption mode to reflection shielding‐dominated electromagnetic interference (EMI) shielding mode, and the switching of the EM function exhibits good reversibility and repeatability based on its shape memory property. By adjusting the compressive strain, LPA aerogel exhibits excellent EM absorption at low strains (20–40%), with an effective absorption bandwidth (EAB) of up to 8.91 GHz, and total EMI shielding effectiveness of up to 28.21 dB at high strains (50–80%), which significantly outperforms the existing intelligent EM materials.