(589d) Electrical Conductivity of Electrospun Polyaniline and Polyaniline-Blend Fibers and Mats

Submicron fibers of polyaniline (PAni) doped with (+)-camphor-10-sulfonic acid (HCSA) and blended with poly(methyl methacrylate) (PMMA) or poly(ethylene oxide) were electrospun over a range of compositions.  Continuous, pure PAni fibers doped with HCSA were also produced by co-axial electrospinning and subsequent removal of the PMMA shell polymer.  The electrical conductivities of both the fibers and the mats were characterized, where a reliable method to characterize fiber conductivity using interdigitated electrodes has been developed and applied to electrospun conductive polymer nanofibers for the first time.  A model is proposed that permits the calculation of mat conductivity as a function of fiber conductivity, mat porosity and fiber orientation distribution; the results agree quantitatively with the independently measured mat conductivities.  The electrical conductivities of the fibers were found to increase exponentially with the weight percent of doped PAni in the fibers, with values as high as 50 ± 30 S/cm for as-electrospun fibers of 100% doped PAni, and as high as 130 ± 40 S/cm upon further solid state drawing.  These high electrical conductivities are attributed to the enhanced molecular orientation arising from extensional deformation in the electrospinning process and afterwards during solid state drawing.