Characterization of polyaniline thin films prepared on polyethylene terephthalate substrate

The polyaniline thin films were prepared by in situ chemical polymerization of aniline on polyethylene terephthalate substrate in the aqueous solutions of citric acid with ammonium peroxydisulfate as oxidant. Using ultraviolet–visible and Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron with energy-dispersive X-ray microscopy, atomic force microscopy, and four-point probe resistivity measurements, pure polyethylene terephthalate and polyaniline thin films were thoroughly characterized. Chemical analysis confirmed the formation of polyaniline with a high degree of oxidation in the form of a smooth thin film (with a thickness of ~ 80 ± 10 nm) on polyethylene terephthalate surface. However, delocalized polyaniline macromolecule aggregates in the spherical shape (with the diameter of ~ 30–40 nm) as well as in the irregular shape (the maximum size of ~ 300 nm) were found on the substrate. The values of average arithmetic roughness, average square roughness, asymmetry, kurtosis, average maximal profile height as well as average maximal height, and depth of roughness were calculated based on the atomic force microscopy data for pure polyethylene terephthalate and polyaniline thin films.