Deposition of Ultrathin Coatings of Polypyrrole and Poly(3,4-ethylenedioxythiophene) onto Electrospun Nanofibers Using a Vapor-Phase Polymerization Method

Electrospun polyacrylonitrile (PAN) nanofibers were successfully coated with polypyrrole (PPy) or poly(3,4-ethylenedioxythiophene) PEDOT layers. To obtain ultrathin coatings on highly porous nanofibrous webs, we adapted a two-step vapor-phase coating process usually used to produce ultrathin films. Ferric tosylate (FeTos) was chosen as the oxidant, because of its solvent-free templating effect that produces highly ordered polymer coatings with improved electronic properties. The concentration of the oxidant solution was found to be a key parameter for the preservation of the open porosity in the nanofibrous mats. Coating thicknesses varied from 5 to 12 nm depending on the polymer and oxidant concentrations. The coatings were strongly attached to the PAN nanofibers and presented some degree of crystallinity and high conductivities. PEDOT-coated nanofibers displayed good electrochemical properties without the need of an additional current collector, making them excellent candidates for the fabrication of flexible electronic devices.