Dopamine-induced high fiber wetness for improved conductive fiber bundles with striated polypyrrole coating toward wearable healthcare electronics

[Display omitted] •Fiber bundles with striated PPy coating, inspired by the striated muscle fiber bundles, was developed.•Dopamine-induced high fiber wetness promoted the formation of bionic structures.•DCFBs showed high-strain-insensitive conductivity and exceptional durability.•DCFBs intelligently responded to electrons/light/pressure, showing potential for wearable healthcare electronics.•A straightforward and versatile technique was offered to produce wearable electronics. Stretchable conductive fibers have shown considerable promise in the field of wearable healthcare electronics, but their widespread application has been impeded by the complexity of their manufacturing processes and their susceptibility to electrical failure under significant deformations. In response to this challenge, this study proposes an approach that harnesses dopamine to enhance the wettability of commercial polyurethane (PU) multifilaments. This enhancement facilitates the penetration of aqueous solutions into the core layer of the multifilaments, thereby enabling the polymerization of a striated polypyrrole (PPy) coating on the monofilament surface of the multifilament core layer. The resulting dopamine-induced composite fiber bundles (DCFBs), drawing inspiration from the structure of striated muscle fiber bundles, demonstrates insensitive conductivity at a high tensile strain of 600% and exceptional durability exceeding 40,000 cycles, as the bionic structure mitigates the effect of PPy coating cracks on overall conductivity. The bionic DCFBs holds potential for applications in stretchable electrical circuits, all-weather wearable thermal therapy devices, and pressure sensors for Moss Code communication and human state detection. This work presents a straightforward and versatile technique for producing highly stretchable fibers with multilayer conductive coatings featuring microstructures in the context of wearable healthcare electronics, utilizing commercial fibers as the primary material source.