Detection of corrosion inhibitor adsorption via a surface-enhanced Raman spectroscopy (SERS) silver nanorods tape sensor

In this work, surface-enhanced Raman scattering (SERS) strategy was utilized for the on-site detection of corrosion inhibitors using a silver nanorods anchored transparent tape sensor. SERS detection realized the intense enhancement of Raman signals from inhibitors to characterize their adsorption behavior on metallic surfaces. Benzotriazole (BTA) molecules were employed as corrosion inhibitors for the protection of AA2024-T3 aluminium alloy in 3.5 wt.% NaCl solution. Electrochemical impedance spectroscopy (EIS) measurement and surface characterization confirmed the superior corrosion inhibition performance of BTA. SERS assessment elucidated that the Raman signals of BTA on AA2024-T3 surface increased gradually with the increase of inhibitor concentration and immersion time. By comparing the EIS and SERS results, it is shown that the SERS intensity was positively correlated with the resistance of the inhibitor film (Rf) and inversely correlated with the capacitance of the inhibitor film (Qf), which indicated that the increased BTA adsorption offered superior inhibitive property against the corrosion of AA2024-T3 in saline solution. The SERS tape developed in this study can be used as a versatile sensor to monitor the dynamic adsorption process of corrosion inhibitors with no restriction on substrate materials.