Multi-configuration synergistic modulation of MXene/poly-Schiff-base/Fe₃O₄ aerogels with enhanced microwave absorption, thermal insulation, and flame retardancy

Multi-configuration modulation strategies play a pivotal role in enhancing electromagnetic wave absorption (EMWA) performance by simultaneously tuning dielectric, magnetic, and geometric characteristics. In this work, a poly-Schiff-base (PSB) is synthesized in situ on amino-functionalized Ti₃C₂T_x-MXene to form a MXene/PSB hybrid, wherein carrier concentration and mobility are effectively optimized by adjusting the MXene content. Subsequently, Fe₃O₄ nanoparticles are confinedly grown on the MXene/PSB framework. Driven by a liquid nitrogen-induced temperature gradient, MXene/poly-Schiff-base/Fe₃O₄ (MPF) aerogels with ordered channel structures are successfully fabricated. The effects of electronic configuration, magnetic domain configuration, and geometric configuration on EMWA performance are systematically investigated. The undirectional MPF aerogels demonstrate a minimum reflection loss (RL_min) of −62.09 dB, while the directionally structured aerogels exhibit a wide effective absorption bandwidth (EAB) of 5.89 GHz. Density functional theory calculations and micromagnetic simulations are employed to elucidate the underlying EMWA mechanisms. Furthermore, frustum- and full-pyramid metamaterial structures deliver an ultra-broad EAB of 36.1 GHz and an ultra-low RL_min of −74.2 dB, respectively. In addition to outstanding EMWA performance, the MPF aerogels demonstrate excellent radar stealth capability, with a maximum radar cross-section reduction of 30.04 dB·m², as well as thermal insulation and flame-retardant properties. These results highlight MPF aerogels as a promising multifunctional structural platform for next-generation advanced EMWA materials.