Synthesis and characterization of conductive polypyrrole with improved conductivity and processability

BACKGROUND: The solubility and conductivity of chemically synthesized polypyrrole (PPy) are dependent on the synthesis procedure and composition. Enhanced processability of PPy with high conductivity can be achieved using the anionic polyelectrolyte poly(styrene sulfonate) (PSS). RESULTS: High-conductivity PPy with better processability was successfully synthesized by in situ chemical oxidation polymerization using various concentrations of PSS. Elemental analysis results show that the C/S and N/S molar ratios of the PPy fabricated in the presence of PSS are in good agreement with theoretical values for PPy-SO4. The S/N ratio increases with increasing PSS content, indicating the high doping level for PPy as the PSS content increases. Scanning electron microscopy and high-resolution transmission electron microscopy images show that the fabricated PPy has spherical structures with the average particle size for the pure PPy being about 250 nm and markedly decreasing to 20-40 nm with the addition of PSS. CONCLUSION: The conductivities of PPy synthesized with a PSS/pyrrole monomer weight ratio of 0.25 are about five times higher than that of PPy matrix. These results are perhaps due to the part played by PSS serving as a dopant to be incorporated into the PPy structure to improve the conductivity of the fabricated PPy. (c) 2009 Society of Chemical Industry