In-situ electrospun nanofiber encapsulation for high-performance, breathable, and adhesive flexible dry electrodes

Abstract Long-term continuous electrophysiological monitoring is crucial for accurate health assessment. However, the practical implementation of flexible dry electrodes is frequently constrained by difficulty of simultaneously achieving high stretchability, stable skin adhesion, and sufficient breathability. This work presents a flexible electrode encapsulation strategy utilizing an in-situ electrospinning process integrated with direct-write transfer to fabricate embedded flexible composite electrodes. A composite of poly (3,4-ethylenedioxythiophene)/poly (styrene sulfonate) and silver nanowires was embedded within a poly (vinyl alcohol)–glycerol substrate, yielding epidermal electrodes exhibiting high conductivity, low Young’s modulus, and superior stretchability. The electrode exhibits low impedance (18 Ω) and biomimetic mechanical properties (Young’s modulus of 1.23 MPa), with minimal resistance variation prior to exceeding 80% strain. Significantly, an in-situ nanofiber encapsulation technique was introduced to address the poor skin adhesion characteristic of dry electrodes. This approach achieves a breathability rate 3.5 times higher than that of medical polyurethane tape encapsulation while maintaining effective waterproofing. A 12 h patch test on human skin revealed no irritation, confirming excellent biocompatibility. In practical use, the electrode enables stable acquisition of long-term electrocardiogram signals during continuous wear, offering a comfortable and user-friendly solution for wearable dry electrodes in prolonged electrophysiological monitoring.