Synergistic integration of mechanical robustness and electromagnetic wave absorption in hierarchical composite sponge-based elastomers via multi-scale heterogeneous interface engineering

High-performance absorbers play a crucial role in reducing electromagnetic pollution and protecting human health. However, most of them exhibit unsatisfied in mechanical stability and cyclicity, which restricts their practical applications. In this study, a novel composite sponge-based elastomer was fabricated using a simple filling and hot-pressing strategy. High aspect ratio conductive carbon nanotubes and magnetic flaky iron powders were dispersed Ecoflex and filling in the polyurethane sponge framework, forming a multi-scale structure with rich heterogeneous interfaces, which further enhanced the effective electromagnetic wave absorption (EWA). The composite elastomer achieved a minimum reflection loss value of −59.74 dB and an effective absorption bandwidth value of 4.24 GHz with a thickness of 2 mm. Notably, its radar cross-section scattering attenuation reached a remarkable value of 34.45 dBm 2 . Moreover, it exhibited excellent mechanical properties, including high elasticity, compressibility, and a tensile strain of up to 250 %. This work not only provides valuable insights into improving electromagnetic performances through multi-scale structure design, but also demonstrates the potential for developing high-performance functional materials with superior EWA capabilities to meet complex electromagnetic protection requirements. • Construct multi-scale architectures from 1D to 3D with abundant heterostructures. • Enhanced microwave absorption of −59.74 dB with wide absorption bandwidth. • Reentrant microstructure for high fatigue resistance under efficient stretching. • Rich heterogeneous interfaces and synergistic multiple loss mechanisms for EWA.