Fabrication of a Curcumin@Cu‐BTC MOF Smart Anti‐Corrosion Coating for Copper

Abstract The curcumin@Cu(II)‐benzene‐1,3,5‐tricarboxylate metal‐organic framework (Cur@Cu‐BTC MOF) coating, as a pH‐sensitive smart anti‐corrosion coating, has been synthesized by encapsulating Cur, as a green inhibitor, in Cu‐BTC MOF. The characteristics of the coating were investigated by scanning electron microscope (SEM) images, energy dispersive X‐ray spectroscopy (EDS), elemental scattering map, FTIR spectroscopy and X‐ray diffraction (XRD) patterns. Corrosion parameters of Cur@Cu‐BTC MOF smart coating in 3.5 % NaCl corrosive solution were investigated using potentiodynamic polarization (Tafel) plots and electrochemical impedance spectroscopy (EIS). Indeed, curcumin loading into Cu‐BTC MOF makes the coating more compact. The inhibition efficiency of Cur@Cu‐BTC MOF coating is 72.57 %. Also, when curcumin is loaded into Cu‐BTC MOF, its consumption is about 6 times lower than using it directly as an inhibitor. Also, the anti‐corrosion performance of the smart coating was measured in different immersion times in 3.5 % NaCl solution. Using UV‐vis spectrometry, it was found that the synthesized Cur@Cu‐BTC MOF nanocapsules have a loading capacity of 16.6 % for curcumin. Cur@Cu‐BTC MOF acts as a smart coating and responds to the decreasing of the local pH caused by the corrosion reaction. Encapsulated curcumin is released in response to the pH stimuli and acts as a corrosion inhibitor.