Composite fluorescence probe towards a smart coating for early corrosion detection of carbon steel

Herein, a composite fluorescent probe was developed as a smart indicator in acrylic resin-based coatings for the early detection of steel corrosion. The Fe3+-sensitive Rhodamine B derivative probe (Rxbxja) was synthesized, and the SiO2 nanoparticle-supported probe S-Rxbxja was prepared through the hydrolysis of tetraethyl orthosilicate (TEOS). The successful synthesis of S-Rxbxja was confirmed using a variety of techniques i.e. SEM and FTIR. A fluorescence microscope was utilized to assess the self-reporting performance of coatings. EIS and seawater immersion tests were employed to evaluate the corrosion resistance of the coating. The fluorescence test results revealed the absence of premature fluorescence in the composite coating, owing to the exceptional compatibility between S-Rxbxja and the coating. The scratched area in the 0.5 wt% sensor-doped coatings exhibited fluorescent and colorimetric dual-channel signals after soaking in 3.5 wt% NaCl solution for 2 h before any visible corrosion phenomenon. The EIS results demonstrated that the |Z|(0.01Hz) value of composite coating maintained 10(7) Omega cm(2) even after being immersed in a 3.5 wt% NaCl solution for 7 days, indicating the excellent anti-corrosion properties of the S-Rxbxja coating. Moreover, mechanical property tests showed that the S-Rxbxja coating had excellent mechanical properties due to the introduction of SiO2 nanoparticles.