Cathodically electrodeposited nitrogen-doped carbon dot–acrylic nanocomposite coatings: a dual-function corrosion barrier and real-time corrosion sensor†

Abstract

In this study, nitrogen-doped carbon dots (N-CDs) were successfully incorporated into an acrylic-based cathodic electrodeposition (CED) coating to develop an advanced nanocomposite system. The N-CDs, synthesized via a hydrothermal method, were directly integrated into the electrodeposition bath without requiring isolation, simplifying the fabrication process. The resulting coatings demonstrated enhanced mechanical strength, improved adhesion, and superior corrosion resistance compared to conventional acrylic coatings, increasing the impedance by a factor of 10⁴. In addition, the fluorescence quenching property of N-CDs in the presence of Al³⁺ was utilized for real-time corrosion monitoring. A simple pH-paper-like sensor was fabricated using N-CDs as an ink, enabling naked-eye detection of aluminum corrosion through a “turn-off” fluorescence mechanism. This dual functionality—both as a corrosion barrier and a corrosion sensor—presents a novel approach to material protection and monitoring. This study highlights the potential of N-CDs in the development of next-generation intelligent coatings for structural materials.