Synthesis and characterization of polypyrrole polymer thin film and the effect of adding silver nanoparticles (PPY/AgNPs)

Abstract

In this research, a chemical oxidative polymerization process was used to prepare polypyrrole (PPY). The characterization of polypyrrole thin films pure and dopped with silver nanoparticles (AgNPs) at different weight ratios of AgNPs (i.e., 5, 10, and 15 wt%) was studied. The thin films were prepared via the drop casting method and flung down on a clean glass substrate at room temperature. Using FT-IR, XRD, and AFM, the system and facet morphology of the thin films were investigated. FTIR analysis of undoped PPY powder revealed distinctive vibrational frequencies of  PPY undoped. Strong absorption bands at 3653 cm-1 (N-H stretching), 2342 cm^-1 (nitridation), and peaks at 1542, 1459 cm^-1 (C=C, C=N vibrations) were observed. Other peaks at 1176 cm^-1 (C-N stretching), 1039, 964 cm-1 (C-H vibrations), 893, 782 cm-1 (C-H bend deformation), 670 cm^-1 (C-C deformation), and 590 cm^-1 (polypyrrole presence) were identified. The results showed that the FT-IR spectra of pure ppy and the spectra of PPY/AgNPs composites were similar. The single XRD data also showed that ppy is amorphous and The distinctive peak of polypyrrole was found at (2θ) 24.35◦, indicating the short-range arrangement of PPy chains the interlayer distance (d) between the measured value of spacing for PPY was 3.6599 A⁰. Additionally, By using AFM, the parameters Ra, R.M.S, and G.S. were determined for PPY doped AgNPs thin films. These values increased with higher doping percentages. For undoped PPY thin film, values were (2.557nm, 3.299nm, 33.40nm) while for doped films with 5%, 10%, and 15% AgNPs, values were (3.397nm, 4.859nm, 46.12nm), (9.328nm, 11.90nm, 66.33nm), and (13.87nm, 19.28nm, 86.89nm) respectively. the AFM results for all thin films of PPY undoped and composites doped with silver nanoparticles (PPY/AgNPs) demonstrated that the values of grain size (G.S.) and root-mean-square (R.M.S.) roughness average (Ra) increase as the number of AgNPs increases.