Intelligent radar/infrared stealth materials exhibit the capacity to dynamically modulate their radar/infrared stealth performance under different environmental backgrounds, which is of critical importance in military applications. In this paper, a dynamically modulated radar/infrared stealth composite is integrated by combining polyimide (PI) foam in its bottom, PI foam/carbon nanotube (CNT)/anisotropic iron (Fe)/vanadium dioxide (VO₂) in its middle, and VO₂ coating on its top. The unique phase transition characteristic of VO₂ effectively promotes significant changes in the conductivity, emissivity, and electromagnetic parameters of the composite foam, thereby motivating the intelligent regulation of radar/infrared stealth performance. Consequently, the radar stealth performance of composite foam can be switched between −4.17 dB at 30 °C and −61.69 dB at 120 °C at a thickness of 2.36 mm. Moreover, the bottom-designed polyimide thermal barrier layer can effectively block thermal radiation, thereby contributing to reducing surface temperatures. Simultaneously, VO₂ coating on the surface exhibits lower infrared emissivity after phase transition. The synergistic effect of reduced surface temperature and infrared emissivity contributes to the realization of intelligent infrared stealth. The present work proposes a promising strategy for designing actively adjustable stealth materials to cope with multi-band military detection in complex operational scenarios.

Researching and manufacturing materials that possess both electromagnetic interference (EMI) shielding and infrared stealth capabilities is of great significance. Herein, an ultrathin polyimide-based nonwoven fabric with low-reflection EMI shielding/infrared stealth performance is successfully fabricated by in-situ loading of Fe₃O₄/Ag nanoparticles on the surface of polyimide (PI) fiber (PFA), and followed by bonding with a commercial Cu/Ni mesh. The synergistic assembly of PFA and Cu/Ni promotes the rational construction of hierarchical impedance matching, inducing electromagnetic waves (EMW) to enter the composite and be dissipated as much as possible. Meanwhile, the existence of Cu/Ni mesh on back of PFA facilitates the formation of electromagnetic resonance and destructive interference of EMW reflected from composite, leading to a lower-reflectivity (0.26) EMI shielding performance of 58 dB within 24–40 GHz at a thinner thickness (430 μm). More importantly, the fluffy PFA nonwoven fabric and metal Cu/Ni mesh endow composite with good thermal insulation and low infrared emissivity, resulting in excellent infrared stealth performance in various environments. As a result, such excellent compatibility makes it possible to become a promising defense material to be applied in military tent for preventing electromagnetic and infrared radiation.

Designing and fabricating efficient electromagnetic interference (EMI) shielding materials becomes a significant and urgent concern. Hence, a novel ultrathin, flexible, and oxidation-resistant MXene-based graphene (M-rGX) porous film is successfully fabricated by electrostatic self-assembly between MXene and graphene oxide (GO) nanosheets, and subsequently thermal annealing under hydrogen-argon atmosphere. The rapid breakaway of functional groups on GO and MXene sheets induces formation of porous conductive network in film, thereby facilitating efficient shielding for incident electromagnetic waves. The optimal absolute shielding effectiveness (SSE/t) value of 76,422 dB·cm²·g⁻¹ can be achieved at a thinner thickness of 15 μm. More importantly, the effective removal of functional groups on MXene conspicuously improves the oxidation resistance of the film, endowing it with an excellent durability (12 months) in EMI shielding performance.