A self-adhesive breathable Janus fibrous membrane for electronic skins with long-term comfort and reliability

Electronic skins (E-skins) capable of acquiring various biosignals show great potential in health monitoring and disease diagnosis. However, conventional elastomeric film-based E-skins lack breathability, moisture-wicking and adhesion properties, leading to sweat accumulation and signal degradation. Newly developed Janus E-skins enable high moisture permeability, but lack inherent self-adhesion. Therefore, developing E-skins with simultaneous air/moisture permeability and self-adhesion remains a persistent challenge for ensuring long-term comfort and device stability. Herein, we report a bilayer self-adhesive breathable Janus fibrous membrane (SABJFM) (~180 μm) for E-skins, featuring a simple structure with a nanoporous hydrophilic layer and a microporous hydrophobic adhesive layer. By combining wettability and pore size gradient, the SABJFM can quickly transport sweat from the skin/E-skin interface to the outside while preventing backflow, thus keeping the skin dry and cool. Meanwhile, the SABJFM ensures a conformal adhesion to skin, greatly enhancing the stability and reliability of the measured signals. As an ideal versatile substrate for E-skins, the SABJFM has been successfully implemented in epidermal electrodes and pressure sensors, demonstrating stable biosignal monitoring under both dry and sweaty skin conditions. This advancement propels the development of next-generation E-skins with exceptional thermal-moisture management and reliable self-adhesion, achieving superior device performance and prolonged wearing comfort.