Self-healing anti-corrosion powder coatings via PDMS-infiltrated mesoporous silica

This study introduces a self-healing strategy for anti-corrosive powder coatings, addressing the inherent challenge of micro-defect formed during curing that compromises long-term corrosion resistance. A healing agent, comprising polydimethylsiloxane (PDMS)-infiltrated mesoporous silica particles, was synthesized and integrated into polyester coatings to autonomously repair micro-cracks and conduits. Various characterization confirmed successful PDMS infiltration into silica carriers and uniform dispersion within the coating matrix. Electrochemical impedance spectroscopy demonstrated three orders of magnitude increase for PDMS-modified coatings, while neutral salt spray testing revealed an 62 % reduction in delamination width compared to unmodified control. Time-of-flight secondary ion mass spectrometry validated PDMS migration, which forms a hydrophobic barrier that impeded electrolyte ingress. The autonomous repair mechanism was detailed illustrated while the migration dynamics of healing agent was characterized through scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy elemental mapping and X-ray photoelectron spectroscopy analysis. This work advances the field by demonstrating a stimulus-free, proactive healing functionality within powder coating matrix, offering a transformative strategy for protective coatings in corrosive environments.