Conducting polypyrrole (PPy) powder synthesized by using FeCl3 x 6 H2O and/or Fe(NO3)3 oxidants was impregnated in silver salt solutions. The stability and decomposition of the material was followed by thermogravimetric measurements. The total silver content was determined by atom absorption spectroscopy (ICP-AAS). The heat and electric conductivities of the composites were measured and correlated with the silver content. The incorporated silver was speciated and measured by X-ray diffraction (XRD). The spectra proved that the chemical state of the silver incorporated into the composite depends on the anion used in the polymerization process. In the case of the polymerization in a nitrate ion containing solution, the impregnation leads exclusively to the formation of metallic silver. The size distribution of the AgCl and Ag nanoparticles, determined from transmission electron microscopy (TEM) pictures in the different composites, proves the formation of a rather uniform species below 10 and 7 nm, respectively. The observations can be correlated with the different interactions in the PPy-chloride/nitrate-silver systems. The redox type interaction based conclusions can be considered as a guide during the preparation of other metal-conducting polymer composites.

Poly(3-octylthiophene)/silver nanocomposites (P3OT/Ag) were prepared by impregnating the polymer powder in silver perchlorate salt solutions. The total silver content, up to 6 wt %, was determined by inductively coupled plasma atomic absorption spectroscopy (ICP-AAS). The electric conductivities of the composites were measured and correlated with the silver content. Conductivity increased by more than 5 orders of magnitude with silver doping. The incorporated silver was speciated by X-ray diffraction (XRD). Silver was found in the form of both Ag and AgCl, predominantly in metallic nanocrystallites. The size distribution of the nanoparticles, determined from transmission electron microscopy (TEM), was found to be bimodal with two maxima around 3 and 17 nm, correlating with the two forms of silver in the composite. Increased conductivity was interpreted by results obtained by photoacoustic Fourier transform infrared spectroscopy (PAS-FTIR). The observed large Seebeck coefficient of P3OT is promising from the point of view of thermoelectric application.

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