Sandwich-like high-efficient EMI shielding materials based on 3D conductive network and porous microfiber skeleton

Abstract

High-efficient and durable electromagnetic interference (EMI) shielding materials are urgently needed to address electromagnetic wave pollution. In this study, Ti3C2TX MXene and silver nanowires (AgNWs) were integrated at a porous microfiber skeleton (PMS) via a dip-coating method to form a sandwich-like conductive network, followed by a polyurethane (PU) fixation. Firstly, PMS was dipped with AgNWs dispersion (1D AgNWs acts as the interlayer) and then immersed in Ti3C2TX MXene nanosheets suspension (2D Ti3C2TX MXene acts as the upper and lower layers). Finally, an EMI shielding material with a sandwich-like conductive network was constructed by immersing it in diluted PU solution at ambient temperature for fixation. The conductivity of the resultant shielding material is found to be 1896.7 s⸱m-1, correspondingly, the average EMI shielding effectiveness (SE) is as high as 100.1 dB. The ideal conductivity of AgNWs and Ti3C2TX MXene, combined with the porous structure of microfiber substrate are believed to impart the resultant material excellent EMI shielding characteristics. In addition, benefiting from the protective effect of the outermost PU thin layer, the coated materials still remain their high shielding performance even after ultrasonic washing for 30 min (100 W), strong acid (pH 2.0), strong base (pH 12.0), 2000 bending-releasing cycles, 2000 folding-releasing cycles, and 1000 twisting-releasing cycles, showing excellent EMI shielding durability.