Multiple Hydrogen‐Bonding Network Engineered Multi‐Layered Polyurethane Aerogels for Absorption‐Dominant Electromagnetic Interference Shielding

ABSTRACT The rapid proliferation of 5G technologies and wearable electronics has intensified electromagnetic interference (EMI), posing a substantial challenge to device reliability and human health. Consequently, lightweight, flexible, high‐performance, and multifunctional EMI shielding materials are urgently demanded. In this work, multi‐hydrogen‐bonded waterborne polyurethane (H‐WPU) was synthesized via polycondensation and combined with MXene and MXene@CoFe 2 O 4 fillers. Using a layered freezing and freeze‐drying strategy, (MXene@CoFe 2 O 4 /H‐WPU, B)‐(MXene/H‐WPU, A)‐(MXene@CoFe 2 O 4 /H‐WPU) EMI shielding aerogels were fabricated. The densely crosslinked hydrogen‐bond network reinforced the H‐WPU and established strong interfacial interactions with MXene and MXene@CoFe 2 O 4 , thereby suppressing filler agglomeration, improving impedance matching, and facilitating the uniform distribution of conductive and magnetic loss pathways. As a result, the B‐A‐B aerogels achieved EMI shielding effectiveness of 81 and 83 dB in the X and Ku bands, respectively, with reflection coefficients as low as 0.14 and 0.11. Excellent absorption‐dominant shielding performance was maintained over a wide range of incident angles. The aerogels also exhibited outstanding mechanical resilience, stable pressure sensing over 1000 loading‐unloading cycles, low thermal conductivity (0.097 W·m −1 ·K −1 ), and robust infrared camouflage performance. This molecular engineering strategy provides a promising route toward next‐generation lightweight, flexible, multifunctional EMI shielding materials integrating sensing and thermal management.