Caterpillar-inspired electromagnetic dual-function cuniculi composites for efficient broad bandwidth microwave absorption

Conductive polymer composites (CPCs) have attracted considerable attention in the field of microwave absorption (MA) due to their lightweight nature and tunable electromagnetic properties. The integration of porous structure into CPCs facilitates simultaneous weight reduction, enhanced MA efficiency, and broad absorption bandwidth. However, achieving high-performance microwave absorption in CPCs with low filler content remains a formidable challenge. Herein, inspired by the segmental body structure of caterpillars, an electromagnetic dual-function hybrid cuniculi composite (EMHC) containing hybrid electromagnetic nanostring (EMNS) nanofillers and segmental microporous structure is developed via in situ sacrificial template synthesis and supercritical plastic expansion methods. The multi-dimensional electromagnetic hollow structure constructed leading to optimized impedance matching and enhanced electromagnetic performance via multiple synergistic loss mechanisms, including multiple reflection loss, dielectric loss, and magnetic loss. As a result, the EMHC with low filler content (5 wt%) and lightweight (0.45 g/cm 3 ) exhibited outstanding MA properties, achieving an ultra-wide effective absorption bandwidth of 6.81 GHz and a minimum reflection loss of −50.25 dB. Notably, the maximum effective absorption region fully encompassed the X-band and Ku-band, with an unprecedentedly low thickness. This study presents a novel strategy for designing and fabricating lightweight, porous polymer composites with superior microwave absorption capabilities, offering significant potential for advanced electromagnetic applications.