Polyaniline and polypyrrole/TiO2 nanocomposite coatings on Al1050: electrosynthesis, characterization and their corrosion protection ability in saltwater media

Abstract

Polyaniline (PANI), polypyrrole (PPy) nanofilms, PANI/TiO2 and PPy/TiO2 nanocomposites were synthesized electrochemically on Al1050 electrode. The formation of PANI and PPy nanofilms and PANI/TiO2 and PPy/TiO2 nanocomposites was characterized by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), UV–visible absorption spectroscopy (UV–Vis), scanning electron microscopy (SEM), energy dispersion X-ray analysis (EDX), and electrochemical impedance spectroscopy (EIS). The comparative morphologic, spectroscopic and electrochemical properties of the prepared PANI and PPy nanofilms and nanocomposites were investigated in this study. The effectiveness of polymer and nanocomposite films in preventing the corrosion of Al1050 was tested in 3.5 % NaCl solution. For corrosion tests, anodic polarization curves and EIS were used to investigate their corrosion protection capability in saltwater solution. The highest, low frequency capacitance values were obtained as CLF = 60.76 and 12.8 mF cm−2 for PANI/TiO2 and PPy/TiO2 nanocomposites, respectively. The results of these studies revealed that the corrosion protection efficiency (PE) of the PANI/TiO2 (PE = 97.2 %), PPy/TiO2 (PE = 97.4 %) nanocomposites coated on Al1050 electrode was higher than that of PANI (PE = 96.4 %), PPy (PE = 94.9 %) and uncoated Al1050 electrodes. These nanocomposites can be used in airplanes, space technology, automobiles, electronics, and building sectors, as well.