Influence of external voltage on the reprotonated polyaniline films by Fourier Transform Infrared spectroscopy

In this paper, we reported the electrical fourier transform infrared (FT-IR) spectra measurements on the reprotonated polyaniline (PANI) thin films. Application of external voltage reduced the intensity in FT-IR spectra and resulted in the shift of band situation. The FT-IR spectra as a function of temperature were also conducted in order to investigate the effect of Joule heating. We found that the influence of CC of phenyl units and the CC of quinoid were quite different as a function of external voltage and temperature. The current–voltage (I–V) curves of the PANI film measured in the range of 0–175 V showed that the resistance kept constant at 0–75 V while it increased from 75 to 175 V. The I–V curves confirmed the presence of Joule heating effect during 75–175 V. According to the experiment results, we concluded that external voltage could produce large average hopping energy, which allowed the charge transfer by hopping between the conducting domains during 0–75 V. The deprotonation of PANI was caused by Joule heating effect, resulting in the decreasing conductivity from 75 to 175 V.