Production of conductive electrospun polypyrrole/poly(vinyl pyrrolidone) nanofibers

This article reports on a new method for the production of Polypyrrole/Poly(vinyl pyrrolidone) nanofibers via the electrospinning of pyrrole solution and subsequent oxidation. The low solubility of polypyrrole makes its electrospinning very difficult. However, low viscosity of pyrrole makes it also unsuitable for electrospinning as well. It was found that increasing the viscosity of pyrrole by adding poly(vinyl pyrrolidone) (PVP) (9% w/w), makes its electrospinning possible. The electrospun pyrrole - PVP nanofibers were collected in a solution of FeCl3 center dot 6H(2)O (2% w/v) and dopant in ethanol and oxidized in-situ, in other words polymerized to PPy (one step method). In another method (two step method), the electrospun pyrrole-PVP-dopant nanofibers were collected on an aluminum foil and then detached from it. To polymerize pyrrole, the nanofibrous mats were immersed in FeCl3 center dot 6H(2)O (2%w/v) solution. P-toluene sulfonic acid (PTSA) and anthraquinone-2-sulfonic acid sodium salt (AQSA) were employed as dopant. The SEM micrographs showed that PPy-PVP nanofibers with an average diameter as low as 440 nm could be prepared. X-ray diffraction patterns showed a crystallinity of about 25.7% for the PPy-PVP nanofibers. FTIR analysis proved the formation of PPy as well as the absence of any considerable reaction between PPy and PVP. The highest electrical conductivity recorded for the AQSA doped PPy-PVP nanofibers with an average diameter of around 830 nm was 5.22 x 10(-1) S cm(-1) which is higher than the highest conductivity of 0.5 Scm(-1) reported for PPy fibers (average diameter = 3 mu m) in the literature.