Silver nanoparticles bridging liquid metal for wearable electromagnetic interference fabric

Stretchable conductive fibers are essential for the advancement of wearable electronic textiles. However, a significant challenge arises as their conductivity sharply decreases when stretched due to disruptions in electronic transport. Coating fibers with soft liquid metal (LM) has emerged as a promising solution. Despite this, there remains an urgent need to develop methods that enhance LM adhesion to substrates while facilitating efficient electron transport pathways. This study demonstrates a novel Ag-LM conductive network strategy for fabricating a thermoplastic polyurethane/polydopamine/silver-LM (TPU/PDA/Ag-LM) fiber membrane. This membrane exhibits outstanding stretchable electromagnetic interference (EMI) shielding performance and is produced through straightforward electrospinning, electroless depositing, and LM coating and activation. The TPU/PDA/Ag fiber membrane is initially prepared via polydopamine-assisted deposition of silver nanoparticles (AgNPs) on electrospun TPU fibers. The presence of AgNPs on the surface of TPU/PDA fibers enhances LM adhesion to the substrate and bridges adjacent LM to establish efficient conductive paths. This interaction benefits from the reactive alloying between AgNPs and LM, where the LM infiltrates the gaps among AgNPs, forming a distinctive LM-Ag alloy layer that uniformly coats the surface of TPU fibers. As anticipated, the unique three-dimensional (3D) interconnected LM-Ag conductive network remains intact during stretching, ensuring strain-invariant conductivity. The fabricated TPU/PDA/Ag-LM fiber membrane demonstrates exceptional EMI shielding effectiveness (SE) of 77.4 dB within the frequency range of 8.2–12.8 GHz and maintains an excellent EMI SE of 37.2 dB under extensive tensile deformation of 300%. Furthermore, the TPU/PDA/Ag-LM fiber membrane shows remarkable mechanical properties and stable Joule heating performance even under significant stretching.