Nanocomposite film formations of polyaniline via TiO2, Ag, and Zn, and their corrosion protection properties

Abstract

• Polyaniline and its nanocomposites with TiO 2 , Ag and Zn coatings on Al1050. • Electrosynthesis and corrosion protection ability in salt-water medium. • PANI, PANI/Ag and PANI/Zn acted as a protective layer on the Al1050. Polyaniline (PANI) and its nanocomposites containing TiO 2 , Ag, and Zn were electrocoated on an Al1050 electrode by cyclic voltammetry. The modified polymer and the nanocomposite films were characterized by cyclic voltammetry (CV), ultraviolet–visible spectrophotometry (UV–vis), Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM), energy-dispersion X-ray analysis (EDX), optical microscopy and electrochemical impedance spectroscopic (EIS) methods. The corrosion behavior of the PANI, PANI/TiO 2 , PANI/Ag and PANI/Zn nanocomposite films on an Al1050 electrode was studied in a 3.5% NaCl solution. The comparison results were obtained by applying Tafel extrapolation and EIS techniques. The findings indicate that PANI/Ag nanocomposite films yielded higher protection efficiency (PE = 97.54%) compared to PANI (PE = 91.41%), PANI/TiO 2 (PE = 91.91%), and PANI/Zn (PE = 92.52%) nanocomposite films. The results show that the addition of nano-materials (TiO 2 , Ag and Zn) into the polymer matrix of PANI enhanced the electrical conductivity of the PANI/Zn film and the corrosion resistance of the polyaniline polymer. These findings were further confirmed by decreasing the oxygen and water permeability and increasing coating adhesion in the presence of TiO 2 , Ag and Zn nanomaterials in the PANI. The EIS measurements indicated that the incorporation of TiO 2 , Ag, and Zn into the coating increased both the charge transfer and pore resistance.