Solvent-free asymmetric dual-conductive network for low-reflection EMI shielding and sensing in eco-friendly PU microfiber leather

Asymmetric double-conductive network bionic microfiber leather has been prepared. • Achieves outstanding absorption-dominant EMI SE (A > 0.9) at only 1.18 mm thickness. • Microfiber leather combines EMI shielding performance and sensing performance. Interior biocompatibility and electromagnetic interference (EMI) have become critical concerns in the design of advanced robotic electronic skins, creating an urgent demand for flexible, durable materials that eliminate solvent residues while providing integrated shielding and sensing functions. This study presents a breakthrough in solvent-free polyurethane (SFPU) microfiber-based skin by architecting asymmetric dual-conductive networks that mimic the hierarchical structure of natural tissue, achieving excellent absorption-dominated EMI shielding performance in the X-band and Ku-band along with reliable sensing capability. In detail, a highly conductive silver nanowires (AgNWs) layer is constructed on the microfiber fabric, serving as the primary electromagnetic reflection layer. Subsequently, an SFPU composite layer with tunable carbon nanotubes (CNTs) loading is coated onto the conductive microfiber fabric to modulate impedance matching. This dual-conductive configuration facilitates an absorption-reflection-reabsorption mechanism, significantly enhancing both overall EMI shielding effectiveness (SE) and the absorption coefficient (A). At a minimal thickness of only 1.18 mm leather exhibits exceptional EMI SE values of 69.05 dB (A = 0.86) in the X-band and 73.26 dB (A = 0.92) in the Ku-band. Remarkably, the material maintains performance integrity after rigorous tests including ultrasonication, cyclic bending and peeling, demonstrating superior EMI shielding stability. This work provides a viable strategy for designing eco-friendly, absorption-dominated, and perceptive EMI-shielding skins for next-generation robotic and human-machine interaction systems. Download: Download high-res image (206KB) Download: Download full-size image