Shape Memory-Driven Intelligent Composite Film for Infrared Stealth and Adjustable EMI Shielding

In the increasingly complex electromagnetic environment, the development of polymer-based electromagnetic interference (EMI) shielding materials with recyclability and adjustable performance holds significant potential. However, achieving precise structural control and tunable functionality remains a major challenge. In this study, a multifunctional shape memory polyurethane (SMPU)-based composite system is proposed that integrates electromagnetic shielding and infrared stealth capabilities with intelligent responsiveness. SMPU is synthesized using polytetramethylene ether glycol, 4,4'-dicarboxydiphenyl disulfide, isophorone diisocyanate, and tannic acid. Through the incorporation of dynamic disulfide bonds and abundant hydrogen bonding, the dynamic polymeric network with self-healing and shape memory properties is established. Furthermore, by introducing silver nanowires (AgNWs) and layered MXene, the stable 1D/2D hybrid conductive pathway is formed via Ag-S covalent bonding and adhesive interfacile interactions, significantly enhancing the system's electrical conductivity stability and interfacial stability. The resulting composite film enables tunable adjustment of EMI shielding effectiveness (EMI SE) from 60.0 to 11.0 dB under 0-30% tensile strain in the X-band (8-12 GHz). During the shape memory recovery process at 50 °C, the surface temperature remains stable at ≈20 °C, demonstrating excellent infrared stealth performance. This work provides both theoretical insights and a practical approach for achieving long-term stability and tunable functionality in intelligent electronic materials.