Polyaniline/cellulose nanocrystal nanorods integrated into waterborne polyurethane coatings for enhanced corrosion resistance

Corrosion is a critical issue in industrial and marine environments, leading to significant economic losses and safety concerns. To address this, polyaniline/cellulose nanocrystal (PANI/CNC) nanorods were synthesized via in-situ chemical polymerization and incorporated into waterborne polyurethane (WPU) coatings to enhance their corrosion resistance. The nanorod structure, leveraging the high dispersibility and conductivity of PANI, along with the stability and surface functionality of CNC, enabled the formation of a uniform and robust composite coating. Systematic characterization, including SEM, FTIR, XRD, UV-Vis, TGA, and zeta potential analysis, validated the structural and thermal properties of the PANI-CNC nanorods. Electrochemical impedance spectroscopy (EIS) and polarization tests demonstrated the superior corrosion resistance of the composite coatings, particularly at 1.0 % PANI content, which achieved optimal performance in 3.5 wt% NaCl solution over 28 days. These results confirm that the synergistic properties of PANI and CNC significantly enhance the barrier and electrochemical performance of WPU coatings, offering a promising strategy for sustainable, high-performance anti-corrosion coatings.