Facile Fabrication of a Stretchable and Flexible Nanofiber Carbon Film-Sensing Electrode by Electrospinning and Its Application in Smart Clothing for ECG and EMG Monitoring

In this study, a carbon electrode was synthesized from carbon black (CB), reduced graphene oxide (rGO), and polyurethane (PU) and subsequently used as the collector for electrospinning. During electrospinning, nanofibers were deposited on the carbon film collector. The carbon electrode and the deposited nanofibers together formed a nanofiber carbon electrode. Finally, a stretchable and flexible nanofiber membrane-sensing electrode was successfully developed and applied in smart clothing for ECG and EMG monitoring. The nanofibers were generated from polyvinylidene difluoride (PVDF) and poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS) via mixing and electrospinning. The addition of a conductive PEDOT/PSS polymer inhibited the formation of beads on the fiber and enhanced the integrity as well as the electrical conductivity of the fiber. In addition, a CB/rGO carbon film was used as the electrospinning collector. The addition of a dispersant to the carbon film improved its electrical conductivity as well as its stretchability. The results show that the nanofiber carbon electrode prepared by electrospinning exhibits a high electrical conductivity (surface resistance = 2.5 × 101 Ω/sq), high mechanical durability (a stable circuit was maintained after 3000 repeated uses), and a hydrophobic surface (water contact angle = 146°). Compared with a traditional commercial wet electrode (Ag/AgCl), the nanofiber carbon electrode developed in this study exhibited good contact with human skin and excellent durability. These merits make the nanofiber carbon electrode suitable for long-term biological signal recording. Furthermore, such an electrode can be integrated into wearable systems for healthcare monitoring.