In situ prepared polypyrrole-Ag nanocomposites: optical properties and morphology

Polypyrrole-silver (PPy-Ag) nanocomposites with various silver contents have been synthesized via a kinetically favorable one-step chemical oxidative polymerization process. The oxidant, ammonium persulfate, was used to oxidize pyrrole monomer for growing chains of PPy. And AgNO3 was used as a precursor for metallic silver nanoparticles. The detailed characterization techniques, UV-Vis-NIR, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction spectroscopy, field-emission scanning electron microscopy, and transmission electron microscopy (TEM), have been used to reveal electronic environment, structure, and morphology of composites as well as as-synthesized PPy. The synthesis environment prior to polymerization has also been investigated by absorption spectroscopy. The TEM images of PPy-Ag nanocomposites reveal that silver nanoparticles are deeply embedded into the polymer matrix in addition to surface adsorption. It is observed that the size distribution of inorganic nanoparticles (ca. 4-10 nm, depending on the metal ion concentrations) as well as structural morphology is altered by the initial concentrations of silver ions.