Synthesis and characterization of pH-responsive mesoporous chitosan microspheres loaded with sodium phytate for smart water-based coatings

Mesoporous micro- or nanocontainers have been indicated to be potential carriers of corrosion inhibitors to modify water-based coatings for self-healing properties and excellent anti-corrosion performance. In this work, the eco-friendly mesoporous chitosan microspheres loaded with green corrosion inhibitor sodium phytate were incorporated in self-healing water-based polyacrylate coating. The microspheres with mesoporous surface, uniform size, and promising pH responsiveness were prepared via the water-in-oil (W/O) emulsion chemical cross-linking method. On this basis, chitosan microspheres loaded with 25.79 wt% sodium phytate were obtained by negative pressure impregnation method and the pH-responsive was demonstrated by the electrochemical impedance spectroscopy (EIS). The results of EIS and seawater immersion tests revealed that artificial defected water-based polyacrylate coating containing 5 wt% chitosan microspheres showed high anti-corrosion performance and exhibited self-healing capabilities due to the release of corrosion inhibitor sodium phytate.