Water-Triggered Shape-Adaptive Superelastic Hydrogels for Electromagnetic Sealing

The irregular gaps between the transmit/receive (T/R) modules, heat dissipation substrates, and radomes in active phased array radars constitute primary pathways for electromagnetic energy leakage and crosstalk. However, existing wave-absorbing materials only rely on the preset shape mode, making them fail to complete conformal coverage and filling of these complex cavities. In this study, we present a shape-autonomous strategy enabled by a reversible "compress-dehydrate/rehydrate-recover" cycle, implemented through a shape-memory wave-absorbing hydrogel that incorporates elastic inorganic fibers and conductive carbon nanotubes. Our approach relies on an elastic fibrous framework coupled with a dynamic hydrogen bond "break-reform" mechanism, which effectively improves the shape recovery performance of the hydrogel. The resulting NFHsc exhibits integrated characteristics, including full recovery under 80% strain, shape-memory behavior, injectability, and effective wave absorption, achieving a minimum reflection loss (RL_min) of -45 dB and an effective absorption bandwidth (EAB) of up to 7.23 GHz. The fabrication of such intelligent adaptive wave-absorbing materials may offer a novel paradigm for the engineering of adaptive multifunctional hydrogels across diverse application scenarios.