Self-assembled electrodes based on polyaniline grafted with reduced graphene oxide and polystyrene sulfonate

In this work, composites based on polyaniline (PAni) grafted with reduced graphene oxide (rGO) were obtained by the in situ chemical polymerization of aniline with rGO (mass ratio of 1 and 2.5%) dispersed into the monomer solutions. PAni and its PAni-rGO composites were used to prepare self-assembled (SA) films by depositing them onto indium tin oxide (ITO) substrates with alternating layers of polystyrene sulfonate (PSS). The structure and morphology of the materials were characterized by Fourier-transform infrared spectroscopy (FT-IR), RAMAN spectroscopy, and scanning electron microscopy (SEM). The oxidation states of PAni and its PAni-rGO composites were characterized by cyclic voltammetry (CV) and UV-Vis spectroscopy during the SA procedure. The electrochemical behavior of the obtained SA films was also characterized by electrochemical impedance spectroscopy (EIS). The EIS results showed a significant decrease in the polarization resistance (Rp), from 1020 to 302 Ω, for the film with 1% of rGO (PAni-1%rGO/PSS) when compared with its unmodified counterpart (PAni/PSS). The synergic effects observed for the PAni-1%rGO/PSS film showed that controlling the rGO mass ratio plays an important role in the improvement of the charge transfer processes, and that this electrode has potential for electrochemical applications, such as sensors and charge storage devices.