Abstract
Thermal and electrical properties of self-doped polyaniline (PAn) having carboxyl group have been investigated. Thermogravimetry-mass spectrometric (TG-MS) results demonstrated that the carboxyl substituent decomposes in the temperature range between 100 and 350°C, followed by the decomposition of the polymer backbone above 350°C. The substituent was suggested to be in the form of -COO- and -COOH from the FT-IR measurements. The existence of the negative carboxyl group resulted from the interaction with the positively charged PAn chain. The thermal decomposition of carboxyl group at 150°C and below did not affect the conductivity of the polymer, but it dropped considerably in the decomposition on temperature above 150°C. This observation indicates that the decarboxylation of the -COOH substituent, which is not associated with the dopant anion, proceeds more readily than that of the -COO- substituent.
