Corrosion-resistant and fluorescent thiol–epoxy ‘click’ coatings reinforced with hydrophobic N-doped carbon dots

Abstract

Multifunctional epoxy composites with enhanced properties were developed by incorporating hydrophobic N-doped carbon dots (NCDs) into a sustainable thiol–epoxy resin system for the first time. NCDs synthesized via the hydrothermal method demonstrated exceptional hydrophobicity, fluorescence, and superior dispersion, ensuring uniform integration into the epoxy matrix. The properties of the optimized 0.5 wt% NCDs–epoxy composite were remarkably enhanced, with a 21% increase in the tensile strength, a 50% improvement in the lap shear strength, a 38% reduction in the coefficient of thermal expansion, and a remarkable corrosion-protection efficiency of 97.5%, as evidenced by potentiodynamic polarization analysis. The fluorescence properties of the NCDs facilitate uniform dispersion, enabling real-time monitoring and potential quality control applications. The eco-friendly nature of this methodology is underscored by the low-temperature, solvent-free curing process, making it suitable for large-scale and sustainable applications. These findings highlight the potential of NCDs-reinforced thiol–epoxy composites as protective coatings for use in harsh environments, particularly under marine conditions, and offer a robust platform for future innovations in sustainable material design.