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

Abstract

Polyaniline (PAN!) and its nanocomposites containing TiO2, 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/TiO2, 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 PAN! (PE = 91.41%), PANI/TiO2 (PE = 91.91%), and PANI/Zn (PE = 92.52%) nanocomposite films. The results show that the addition of nano-materials (TiO2, 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 TiO2, Ag and Zn nanomaterials in the PANI. The EIS measurements indicated that the incorporation of TiO2, Ag, and Zn into the coating increased both the charge transfer and pore resistance. (C) 2015 Elsevier B.V. All rights reserved.