Synthesis and Characterization of Polyaniline-Based Polymer Nanocomposites as Anti-Corrosion Coatings

Polymer nanocomposites of polyaniline (PANI)-based metal oxides (SiO2, CeO2, and TiO2A) were synthesized by in situ chemical oxidative polymerization by rapid mixing in a hydrochloric acid medium to evaluate and compare their performance as anti-corrosion coatings on commercial 1018 steel in a 3.5% NaCl medium. The anti-corrosion coatings were developed by dispersing synthesized nanocomposites on an alkydalic resin (AR) for their subsequent electrochemical characterization. X-ray diffraction (XRD) analyses show that PANI has a certain degree of crystallinity in its structure. The incorporation of metal oxide (MO) nanoparticles (NPs) into the polymer matrix was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS) analyses, while the interaction of nanoparticles with PANI was proven by Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-vis). Thermogravimetric analysis (TGA) reveals that nanoparticles infer greater resistance to the thermal decomposition of PANI. Finally, the use of open circuit potential (OCP) study, Tafel curves, and electrochemical impedance spectroscopy (EIS) showed that coatings made with TiO2A NPs exhibit the best anti-corrosion properties as compared to those synthesized with SiO2 and CeO2 NPs