Studies of thermal decay of electropolymerized polypyrrole using in situ surface-enhanced Raman spectroscopy

In this work, the thermal degradation of polypyrrole (PPy) films was investigated by using in situ surface-enhanced Raman spectroscopy (SERS) for the first time. The results indicate that the decay of PPy in conductivity can be ascribed to the loss in oxidation degree and to the shorter conjugation length of PPy upon heating samples from 25 to 75 °C. Continuously raising the temperature of the sample from 75 to 125 °C results in serious decay. The oxidation degree of PPy is significantly decreased correspondingly. However, the peak assigned to the CC backbone stretching becomes broader due to the thermal decomposition of PPy. At temperatures of samples higher than 125 °C, PPy films lose their conducting properties and no characteristic peaks of oxidized PPy related to the oxidation degrees can be observed. Moreover, the peak of the CC backbone stretching completely disappear due to the complete decomposition of PPy.