Cu-HHTP/rGO nanocomposites with tunable heterointerfaces encapsulated in flexible solid-solid phase change films for self-healing and radar-infrared compatible camouflage

Multispectral compatible stealth materials are essential for modern military platforms to counter diverse detection threats. However, the inherent mechanism conflict between microwave absorption and infrared stealth hampers cross-band stealth in single-material systems. Herein, 2D Cu-HHTP/rGO functional fillers are embedded into a solid-solid phase change polyurethane (SHPEG) matrix to fabricate a flexible, self-healing composite film (Cu-HHTP/rGO/SHPEG) with radar-infrared dual-stealth. A synergistic regulation strategy of Schottky heterointerfaces and electrical conductivity is proposed, which induces a built-in electric field and optimizes dielectric loss. Cu-HHTP/rGO attains outstanding microwave absorption with a minimum reflection loss (RL_min) of −60.49 dB and an effective absorption bandwidth (EAB) of 7.51 GHz. Meanwhile, the dynamic cross-linking network modified with disulfide bonds ensures self-healing ability and structural stability of the SHPEG matrix. Based on the excellent thermal management capacity of SHPEG and the low infrared emissivity of Cu-HHTP/rGO, the Cu-HHTP/rGO/SHPEG film possesses remarkable integrated performance: RL_min reaching −52.8 dB, EAB covering 7.29 GHz, infrared emissivity as low as 0.239 and a phase transition enthalpy of 95.1 J/g. The composite film also exhibits exceptional flexibility, self-healing efficiency, shape stability and mechanical strength. This work provides new insights for resolving multiband stealth conflicts and promotes the development of advanced radar-infrared bifunctional materials.