Effect of morphology of poly(pyrrole) nanostructures on the spinnability and conductivity of solution-spun PU composite fibers for E-Textiles

In recent years, there has been significant growth in wearable e-textiles research for various applications. One of the important requirements for successfully integrating electronic components is the development of flexible and stretchable conducting fibers. In the literature, fibers with high conductivity often rely on high loadings of nano-metallic or carbon-based fillers. We have developed stretchable composite fibers using polyurethane (PU) and poly(pyrrole) (PPy) nanostructures by wet spinning. Poly(pyrrole) nanoparticles (PPyNPs) and poly(pyrrole) nanotubes (PPyNTs) were employed as conductive fillers in concentrations ranging from 2 to 12 wt%. The aspect ratio of these nanostructures profoundly affected the rheology of the PU/DMF spinning dopes, with PPyNTs inducing higher shear-thinning behavior and better viscoelastic properties, compared to PPyNPs, favoring continuous fiber formation. The rheological differences translated into improved spinnability and fiber properties. With the same amounts as PPyNPs, the PPyNTs exhibited better spinnability, enhanced mechanical properties, and significantly greater electrical conductivities. The composite fibers with 12 wt% of PPyNTs showed a high conductivity of 0.21 S/cm compared to 8.6E-8 S/cm with 12 wt% of PPyNPs. Further, the fibers showed high stability in repeated deformations. The fibers may find applications as connecting wires in wearable e-textiles.