Constitution of novel polyamic acid/polypyrrole composite films by in-situ electropolymerization

The preparation and characterization of polyamic acid-polypyrrole (PAA/PPy) composite films are reported in this paper. The thin films were synthesized by electrochemical method from a solution containing controlled molar ratio of chemically synthesized polyamic acid (PAA) and pyrrole monomer. Homogenous films were obtained by incorporating PAA into electropolymerized polypyrrole (PPy) thin film. The concentration of PAA (1.37 × 10^-6 M) was kept fixed throughout the composite ratio analysis, whilst the concentration of PPy was varied from 1.90 × 10^-3 M to 9.90 × 10^-3 M. The PAA/PPy thin films were electrodeposited at a glassy carbon electrode (GCE) and characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Atomic force microscopy (AFM), Scanning electron microscopy (SEM) and voltammetry. The composition that best represented the homogenous incorporation of PAA into PPy matrix was observed at a PAA/PPy ratio of 1: 4.13 × 10^-3. This composite was observed to have two sets of coupled peaks with formal potential 99 mV and 567 mV respectively. The D_e determined from cyclic voltammetry using the anodic peak currents were found to be twice as high (5.82 × 10^-4 cm²/s) compared to the D_e calculated using the cathodic peak currents (2.60 × 10 ^-4 cm²/s), indicating that the composite favours anodic electron mobility. Surface morphology and spectroscopy data support the formation of a homogenous polymer blend at the synthesis ratio of 1: 4.13 × 10^-3.