Multistage porous hybrid aerogel: a multifunctional material for acoustic-electromagnetic-infrared multispectral stealth

Advanced military equipment increasingly demands materials with acoustic, electromagnetic, and infrared stealth properties, yet existing materials are unable to achieve effective multispectral stealth. Based on a multistage porous structure design concept, this study develops an aramid nanofiber (ANF)/flake carbonyl iron powder (FCIP)/polydopamine@biomass porous carbon (PC) composite aerogel (AFPC). This material exhibits not only efficient acoustic, electromagnetic, and infrared multispectral stealth compatibility but also maintains favorable mechanical properties. We constructed a “directional pore channels - multistage pores - heterogeneous interfaces” architecture across macro‑to‑micro scales. Macroscopically, ice-templating regulates the aligned arrangement of ANFs, establishing a directional pore skeleton with low propagation impedance. Mesoscopically, thermodynamic control modulates the porous conductive network of PC to enhance energy dissipation and suppress thermal conduction. Microscopically, FCIP tailors magnetoelectric heterogeneous interfaces to strengthen electromagnetic wave polarization loss, while utilizing the metal’s “mirror-reflection” effect for infrared multireflection. The AFPC aerogels integrate highly efficient multispectral stealth performance, demonstrating noise reduction coefficient of 0.73 (30 mm), minimum reflection loss of -71.53 dB (30 mm), absorption bandwidth of 15.8 GHz (30 mm), thermal conductivity of 46 ~ 48 mW/m·K (10 mm), and infrared emissivity of 0.31 ~ 0.33 (10 mm). These properties significantly surpass those of previously reported multispectral stealth aerogels. This design establishes a paradigm for developing highly efficient multispectral stealth materials, showing substantial potential for advanced military applications.