A combined experimental and theoretical studies on molecular structure and vibrational spectra of polyaniline and polyaniline/silver nanocomposite

•Synthesize of polyaniline and its nanocomposite containing silver nanoparticles.•Products were investigated in terms of morphology and chemical structure.•Results compared with theoretical studies using density functional theory calculation.•Leucoemeraldine-Ag was found to be the actual configuration of PAn/Ag.

In this study, preparation of polyaniline (PAn) and its nanocomposite containing silver nanoparticles was discussed and molecular structure and vibrational spectra of polyaniline and polyaniline/silver (PAn/Ag) nanocomposite was compared with theoretical studies by using density functional theory (DFT) calculation. In density functional theory calculation, different models of PAn and PAn/Ag were established at low pH (pH = 1). The IR vibrational wavenumbers of these models using DFT-B3LYP with 6-31G/DGDZVP were calculated; and it was compared with experimental IR spectrum. Analyzing the comparison of experimental FTIR result and theoretically calculated IR spectra, Leucoemeraldine-Ag was found to be the actual configuration of PAn/Ag at pH = 1.