Water‐Triggered Shape‐Adaptive Superelastic Hydrogels for Electromagnetic Sealing

ABSTRACT 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.