Polypyrrole/silver composites prepared by single-step synthesis

Polypyrrole/silver composites were prepared by single-step chemical oxidative polymerization of pyrrole using silver nitrate as an oxidant in aqueous medium at room temperature. The oxidant-to-monomer mole ratio was varied in these experiments. The time needed for yield to be higher than 70% has been estimated to at least several days. The silver content was 70–80 wt.%, the conductivity of composites was of the order of 1000 S cm−1. The morphology of composites was demonstrated by scanning electron microscopy and that of individual components by transmission electron microscopy. Silver is present mainly as nanoparticles of 50–100 nm size, but also as larger objects. Among polypyrrole nanostructures, nanotubes are the most interesting. The molecular structure of polymer component was characterized by FTIR and Raman spectroscopies, and polypyrrole structure was confirmed. Surface-enhanced Raman scattering at PPy–silver interface was observed. Optical microscopy demonstrated the presence of macroscopic silver plates in the composites and thus illustrated the macroscopic heterogeneity of composites.

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► Oxidations of pyrrole with silver nitrate yields polypyrrole–silver composites.
► Material is composed of two conducting components, a semiconductor and a metal.
► The conductivity of polypyrrole–silver composites typically exceeds 1000 S cm−1.