Environmentally adaptable hydrogels with highly entangled interpenetrating networks for efficient electromagnetic wave absorption

Amidst the escalating peril of electromagnetic pollution stemming from high-power and gigahertz-frequency signals, the imperative to engineer efficacious electromagnetic wave-absorbing materials has emerged as a paramount challenge. Traditional absorbers, such as transition metal oxides and their composites, often lack the ability to promptly mitigate the negative impact of heat accumulation and temperature rise in the absorber. In this work, a highly entangled interpenetrating double network hydrogel was prepared using a multi-step compounding and solvent exchange strategy. A magnetic liquid metal (MLM) was then introduced into the hydrogel matrix to simultaneously enhance its thermal conductivity and electromagnetic energy dissipation capabilities. Furthermore, a “temperature and humidity regulating component” was introduced to stabilize the water content of the liquid hydrogel and alleviate localized heat accumulation. Through the synergistic compensation of multiple loss mechanisms and precise control of electromagnetic parameters, the resulting PP@M − LiCl composite exhibited excellent microwave absorption performance. Specifically, at a thickness of only 0.9 mm, the effective absorption bandwidth (EAB) of PP@M-LiCl-4 covered the entire X-band. Furthermore, this hydrogel possesses excellent mechanical properties, with a tensile strength of 0.85 MPa, an elongation at break of approximately 260%, and maintains excellent recovery after high-temperature dehydration. This research provides important theoretical reference and engineering guidance for the design of environmentally adaptable broadband electromagnetic wave absorbing materials.