Self-supporting ultra-thin sandwich-structured ANFs-PVA/AgNWs films with flame-retardant and electromagnetic interference shielding performance

Due to electronic product miniaturization and acceleration, electromagnetic radiation and thermal accumulation issues are prominent, posing risks to nearby devices and individuals. Developing thin polymer films to block electromagnetic radiation and prevent fires is crucial for smaller, faster electronics. In this study, we successfully fabricated a unique self-supporting ultra-thin sandwich-structured film named ANFs-PVA/AgNWs (APAg), which exhibited exceptional performance in both electromagnetic interference (EMI) shielding and flame retardancy. The introduction of inner AgNWs layer resulted in significant EMI shielding effectiveness (SE) at X-band frequencies, achieving an impressive 47.01 dB with a loading of only 0.10 mg/cm², effectively blocking 99.99 % of electromagnetic waves (EMWs). The ANFs-PVA layers were adopted as the flexible outer layer, endowing the films with excellent flame retardance and good mechanical support due to the high heat resistance of aramid nanofibers (ANFs) as well as the strong hydrogen bonding interaction between ANFs and PVA. The film demonstrated self-extinguishing behavior in vertical burning tests, achieving a flame-retardant rating of V-0. Furthermore, the sandwich structure provides high durability for the EMI shielding performance of the films under different conditions. This study presents a novel approach for fabricating high-performance polymer-based EMI shielding films that hold great potential for applications in electronics and communication technologies.