Aggregation-induced emission luminogens sensors: Sensitive fluorescence ‘Turn-On’ response for pH and visually chemosensoring on early detection of metal corrosion

Hidden corrosion of metal materials can cause catastrophic failure of engineering structures without warning, especially in harsh ocean environments. Thus, convenient, sensitive and effective early detection of metal corrosion has a great significance on the safety control of engineering facilities. In this research, we developed a novel aggregation-induced emission luminogen (AIEgen), TPM (( E )- N -(1 H -indazol-3-yl)-1-(4-(1,2,2-triphenylvinyl)phenyl)menthanimine), applied in epoxy coating, in which the visualization of the early stages of metal corrosion have been realized through a fluorescent ‘Turn-On’ phenomenon. Excellent luminescence response is observed on this coating with only 0.5‰ TPM content. Visible fluorescent ‘Turn-On’ phenomenon can be triggered on the delaminated TPM epoxy coating after immersion in solution at pH = 4 for 5 h, which ensures the rapidity and convenience of corrosion detection. The fluorescent response mechanism and intramolecular charge transfer (ICT) effect are finally discussed by combining the theoretical calculation with the experimental results. This research is an infrequent work on the early detection of the metal corrosion based on aggregation-induced emission luminogens (AIEgens). Moreover, this coating exhibit better corrosion resistance (∼10 10 Ω cm 2 ) on Q235 than that on tinplate and 304 steels, and enhanced the toughness of the coating.