Conductive polymer fibers for sensor devices

Abstract

This chapter introduces the sensor applications of conductive fiber assemblies of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrene sulfonate) (PEDOT:PSS) and regioregular poly(3-hexylthiophene) (P3HT). The scalable conductive multifilament of PEDOT:PSS and poly(vinyl alcohol) (PVA) was fabricated by a coagulation of spinning dope solution in cold methanol. The multifilament was composed of uniform circular fibers with an average diameter of 60 ± 5 μm and showed good enough mechanical properties for textile processes while maintaining electronic conductivity. The foldable textiles based on the PEDOT:PSS/PVA blended fibers worked as flexible electrodes to detect human heartbeats. Uniform P3HT nanofibers are obtained through a continuous electrospinning process using a homogeneous solution of highmolecular- weight P3HT. The P3HT nanofibers are oriented by collecting them on a rotating drum collector. Small physical inputs into the self-standing P3HT nanofiber assemblies give rise to additional contact among neighboring nanofibers, which results in a decreased contact resistance in the directions orthogonal to the nanofiber orientation. The P3HT nanofiber assemblies could detect pressure changes and bending angles by monitoring the resistance changes, and the sensor responses were repeatable. The organic-conductive fibers can be a platform for lightweight wearable electronics.