Study of the Influence of a Mixed Electrolyte of Oxalic Acid and DBSA on the Properties of Co-Deposited Poly(Aniline-Co-Pyrrole)

Aniline and pyrrole copolymers were synthesized for different monomer ratios from a mixed electrolyte containing 0.1M oxalic acid and 0.1M dodecyl benzene sulphonic acid (DBSA) using a 4-step electrochemical method. Results were compared to those obtained for polymers prepared from an electrolyte of oxalic acid only. It was found that the presence of DBSA increases the polymerization rates for polymer deposited from the mixed monomer electrolytes, but not for the homopolymers. For copolymers deposited from monomer mixtures of high aniline content, deposition rates were generally low, due to the low conductivity of these samples. FTIR and cyclic voltammetry results confirm the presence of both monomers in the polymers deposited from the mixed electrolyte, and FTIR indicates that copolymers, rather than mixtures, are formed. Results from AC impedance spectroscopy show that the presence of DBSA results in an increased double layer capacitance for the homopolymers and increased low frequency capacitance for those samples with low pyrrole content.