Correlation between the electrochemical synthesis conditions and the optical properties of polypyrrole

A study of the optical properties of free standing polypyrrole films electrochemically prepared with different electrolyte types is presented. Specular reflectance measurements were performed by FTIR spectroscopy in the range 200–6000 cm−1. The optical constants for polypyrrole films were calculated from the reflectance spectra with Kramers-Kronig technique. The effects of the thermal annealing, in the temperature range 373–423 K, on the reflection spectra of polypyrrole doped with p-toluenesulfonate were investigated. The changes of the reflectance and d.c. conductivity after thermal annealing are discussed in terms of the correlation with the conformational defects of the polymer chains.