Melt-Welding and Improved Electrical Conductivity of Nonwoven Porous Nanofiber Mats of Poly(3,4-ethylenedioxythlophene) Grown on Electrospun Polystyrene Fiber Template

A simple and efficient way of synthesizing conducting polymers on polymer templates and subsequently improving the connectivity between fibers and hence improving the electrical conductivity of nonwoven porous conducting polymer nanofiber mats is reported. The poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer was grown via a vapor-phase polymerization on a nonwoven porous mat of polystyrene (PS) nanofibers containing ferric p-toluenesulfonate (Fe-TS). The PS/Fe-TS nanofibers of diameter similar to 300 nm were electrospun and exposed to 3,4-ethylenedioxythiophene (EDOT) vapors. Two different vapor exposure conditions were studied. The shape of the PS template fibers is preserved best under the vapor exposure condition where the EDOT vapor does not condense on the fiber surface. A better electrical conductivity of the fiber mat can be obtained by condensing the EDOT vapor on the PS template fiber during the polymerization. This allows melt-welding of the fibers, which results in a better connectivity between the fibers. The porous PS-PDEOT fiber mats produced under the melt-welding condition showed a sheet conductivity of similar to 1 S/cm.