Enhanced Charge Transport and Corrosion Protection Properties of Polyaniline-Carbon Nanotube Composite Coatings on Mild Steel

We report on the synthesis and characterization of carbon nanotube (CNT)-doped polyaniline (PANI) composites for enhanced corrosion protection of steel with improved electrical properties. PANI-CNT nanocomposites were prepared through in situ polymerization of aniline in the presence of CNTs. Synthesized nanocomposites were characterized by several analytical methods such as Fourier transform infrared spectroscopy, x-ray diffraction, micro-Raman spectroscopy, and scanning electron microscopy in order to understand the structural, morphological, and molecular aspects of the composites. The doping of CNTs in PANI matrix drastically enhanced the alternating current/direct current (AC/DC) conductivities as well as the dielectric attributes and impedance spectroscopy of the composites. The anticorrosion studies of the prepared composites were performed by using open-circuit potential analysis and potentiodynamic measurements. Compared to stainless steel, PANI-CNT nanocomposites demonstrated excellent anticorrosion behavior. The obtained results showed that 25 wt.% of CNT-doped PANI composite exhibits excellent anticorrosion properties due to electron transmission and passive catalysis.