Interfacial engineering of ultrahigh-performance sandwich-structured composites for multifunctional electromagnetic shielding, infrared stealth, and self-cleaning.

The development of advanced materials that integrate electromagnetic interference (EMI) shielding, infrared stealth, and self-cleaning functionalities into a single flexible architecture remains a formidable challenge in materials science. To address this, we propose an interfacial engineering strategy that constructs a dual mechanical interlock between a nanoporous copper foil (NPCF) core and polydopamine-modified electroless copper-plated ultra-high molecular weight polyethylene (UHMWPE@Cu) outer layers via hot-pressing, achieving robust metal-polymer interfacial adhesion. The resulting sandwich-structured composite exhibits an average EMI shielding effectiveness (SE) of 111.86 dB in the X-band, rivaling that of pure copper foil, alongside a tensile strength of 41.3 MPa. It maintains excellent structural integrity and EMI shielding performance under extreme conditions, including cryogenic exposure, immersion in strong acid/alkali solutions, 1000 bending cycles, and ultrasonic treatment. Furthermore, the composite demonstrates an average emissivity as low as 0.16 within the 7-14 μm infrared atmospheric window and a water contact angle of 114°, thereby integrating prominent infrared stealth and self-cleaning functionalities. This work not only provides an innovative material solution for flexible electronics, wearable devices, and military equipment in harsh environments but also establishes a new interfacial design paradigm for developing next-generation multifunctional composites adaptable to extreme service conditions.