The oxidative polymerization of p-phenylenediamine with silver nitrate: Toward highly conducting micro/nanostructured silver/conjugated polymer composites

Abstract

The oxidative polymerization of p-phenylenediamine with silver nitrate by using various oxidant/monomer mole ratios in aqueous solutions of both acetic and nitric acid was studied experimentally and computationally. The produced micro/nanostructured conducting poly(p-phenylenediamine)-silver composites, reaching the conductivities >104 S/cm, were characterized by conductivity and density measurements, gel permeation chromatography, transmission electron microscopy, UV-visible, FTIR, and Raman spectroscopies. The highest conductivity was 31,700 S/cm for poly(p-phenylenediamine) base-silver (81.4 wt % Ag). The unexpected increase of conductivity after deprotonation of polymer component is discussed on the basis of interfacial electrical barriers and their removal. Theoretical study of the mechanism of p-phenylenediamine oxidation has been based on the AM1 semi-empirical quantum chemical computations of the heat of formation of the reaction intermediates, taking into account the influence of pH and solvation effects. Quantum chemical predictions of molecular structure of poly(p-phenylenediamine) were correlated with spectroscopic findings. © 2011 Wiley Periodicals, Inc.