Synthesis and evaluation of conducting polypyrrole/Al₂O₃ nanocomposites in aqueous and non-aqueous medium

The polymerization of pyrrole (PY) in aqueous or alcohol/water mixed medium in presence of FeCl₃ and nanodimensional Al₂O₃ resulted in the formation of conducting nanocomposites of polypyrrole (PPY)/Al₂O₃. The incorporation of PPY in the composites was endorsed by FT-IR studies. The extent of PPY loading in the composites decreased with increasing amount of Al₂O₃ in the initial feed at a fixed PY and FeCl₃ amount, respectively. For alcohol-water systems, the extent of PPY loading in the composites decreased with increasing alcohol concentration in the mixture with fixed amount of Al₂O₃, FeCl₃ and PY, respectively. SEM and TEM studies revealed interesting morphological features for the composites prepared under various conditions and confirmed the formation of monodispersed composite particles of diameters in the nanometer range. TG analyses revealed the enhanced thermal stabilities of the nanocomposites relative to the base polymer. The dc conductivities of the PPY/Al₂O₃ nanocomposites were in the order of (63 ± 3to 33 ± 5) × 10^-2 S/cm, and the values increasing with decreasing Al₂O₃ loading in the nanocomposites in aqueous medium but in case of alcohol-water medium, dc conductivities increases with increasing alcohol content in the medium. Some of these nanocomposites could be obtained as stable dispersion during synthesis.