Zinc dimethacrylate-modified epoxy coating for corrosion protection and self-healing

Corrosion-related asset losses and safety risks are increasing the need for smarter protective coating strategies. In this work, zinc dimethacrylate (ZDMA) was incorporated into epoxy coatings for enhanced corrosion protection for carbon steel. The successful integration of ZDMA into the epoxy network was confirmed by Raman and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), which evidenced Zn 2+ coordination with specific functional groups in the matrix via the formation of coordination bonds. Reduced water absorption was observed in the ZDMA-modified coatings compared to the neat epoxy coatings, likely due to a denser cross-linked structure and improved barrier properties. Electrochemical Impedance Spectroscopy (EIS) revealed that the modified coating exhibited excellent corrosion resistance in a 3.5 wt% NaCl solution over a 180-day immersion period. The modified coatings maintained a high low-frequency impedance modulus and phase angles near −90° across a broad frequency range, indicating sustained capacitive behavior and effective barrier performance. Notably, when impedance decreased due to a presence of a defect and onset of localized corrosion, subsequent measurements showed a rapid recovery of the impedance to the values measured on the intact coating, demonstrating a self-healing response, additionally supported by micro-scale SVET and EDS findings.