Studies on electrosynthesized leucoemeraldine, emeraldine and pernigraniline forms of polyaniline films and their supercapacitive behavior

In the present work, we report the supercapacitive performance of electrosynthesized leucoemeraldine (L), emeraldine (E) and pernigraniline (P) forms of polyaniline on to stainless steel (304) substrates. The properties of these forms were studied using range of techniques such as, X-ray diffraction (XRD), Fourier transforms infrared (FT-IR) and Raman spectroscopy, scanning electron microscopy (SEM), surface wettability and optical absorption. Amorphous nature of all three forms polyaniline has been revealed from XRD analysis. The formation of elemental bonds of polyaniline films have been confirmed by FT-IR and Raman spectroscopic techniques. Nanocrystalline nature for three forms and some extent of overgrowth are observed for pernigraniline (P) form. Surface wettability measurement showed hydrophobic to hydrophilic change with water contact angles 102°, 65° and 86° for leucoemeraldine (L), emeraldine (E) and pernigraniline (P) forms, respectively. Optical absorption spectra showed the presence of transition bands for emeraldine (E) and pernigraniline (P) forms. The supercapacitive behavior of these forms was studied using cyclic voltammetry and showed highest specific capacitance of 258 F g−1 for emeraldine (E) form, when compared with other forms of similar thickness.