Structural, electrical and microwave properties of conducting polypyrrole thin films: effect of oxidant

This article demonstrates the synthesis of conducting polypyrrole (Ppy) thin films using different oxidants and their effect on structural, electrical and microwave properties of polypyrrole thin films. The prepared films are characterized for XRD, FTIR, SEM, Raman, DC electrical conductivity and microwave properties. The XRD analysis proves the polypyrrole films prepared using various oxidants are mostly of amorphous nature. The FTIR spectrums show that the presence of all characteristics absorption peaks of Polypyrrole. The morphological study shows massive change in SEM micrographs of polypyrrole thin films synthesized via different oxidants while the bands observed at 936 cm^–1 and 971 cm^–1 in the Raman spectra reveals the formation of polarons and bipolarons which confirms the conducting nature of polypyrrole thin films. The DC electrical conductivity study shows maximum electrical conductivity up to 135.8 × 10^–3 S cm⁻¹ achieved for the Ppy films synthesized using oxidant K₂S₂O₈ also it show better microwave absorption properties in the 8–18 GHz frequency region. Similarly, Shielding effectiveness value observed for Ppy thin film prepared using oxidant K₂S₂O₈ is relatively high which is up to 14.75 dB i.e. ∼90% microwave radiations are absorbed at 10.2 GHz. (paper)