Janus Nanofiber Membranes for Wearable Electronics: Integrated Conductivity, Unidirectional Water Transport, and Multimodal Responsiveness

The simultaneous integration of high electrical conductivity, directional liquid transport, mechanical robustness, electrothermal response, and antimicrobial activity within a single material platform remains a major challenge for wearable electronics. Here, we report a hierarchically engineered Janus conductive nanofibrous composite (JCNC) membrane constructed via multiscale interfacial engineering to overcome these limitations. The asymmetric architecture consists of a superhydrophilic conductive polyurethane (PU) nanofiber layer, where polydopamine-assisted in situ growth of silver nanoparticles is further modified with cysteine to enhance hydrophilicity coupled with a hydrophobic top layer of electrospun acidified carbon nanotube (ACNTs)-embedded PU fibers. This rational design establishes continuous conductive pathways while generating a tunable wettability gradient, thereby achieving ultrahigh electrical conductivity (1214 S cm^-1) and fast unidirectional water transport (9 s). The JCNC membrane further exhibits multifunctionality, including satisfactory electrothermal conversion, good electromagnetic interference (EMI) shielding (102.14 dB), and broad-spectrum antibacterial efficacy against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>. Importantly, it retains mechanical resilience and electrical stability under repeated deformation, enabling reliable operation as a high-sensitivity strain sensor. This study establishes a generalizable interfacial design strategy for next-generation moisture-adaptive, skin-conformal, and intelligent electronic systems.