Nanofiber-based self-adhesive electrode using self-doped PEDOT and polyurethane

In on-skin electronics, flexibility, gas permeability, and self-adhesiveness of electrodes are essential for measuring biosignals and ensuring stable attachment to the skin during human motion. Nano (micro) sheet electrodes offer sufficient flexibility and gas permeability, making them suitable for biosignal measurement. However, achieving both high conductivity and self-adhesion in nano (micro) sheet electrodes remains challenging. Additionally, conventional conductive materials are typically fabricated on only one side of an insulating film, preventing full conductivity and necessitating wire insertion between the skin and the electrode. To address these issues, we developed a fully conductive microsheet electrode using polyurethane and self-doped poly(3,4-ethylenedioxythiophene). The electrode exhibits a sheet resistance of 2–4 kΩ/□, an adhesion energy of 60 µJ/cm2, and air stability for up to 3 weeks. Using these electrodes, we successfully recorded electrocardiograms in a sauna environment, where temperatures exceed 90 °C and heavy sweating occurs.