Preparation of supramolecular corrosion-inhibiting nanocontainers for self-protective hybrid nanocomposite coatings

Smart corrosion-inhibiting coatings generate or release an inhibitor only when demanded by the initiation of corrosion. Supramolecular nanocontainers of the alpha-cyclodextrin (alpha-CD) corrosion inhibitor were prepared by inclusion complex (IC) formation between alpha-CD and 2-mercaptobenzothiazole (MBT) or 2-mercaptobenzimidazole (MBI) under various conditions (at room temperature and under sonic energy). The structure of the supramolecular nanocontainers was characterized by hydrogen nuclear magnetic resonance (H-1-NMR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). Supramolecular nanocontainer formation between MBT and MBI with alpha-CD in solid phase was emphasized by the significant differences between the H-1-NMR, FTIR and XRD spectra of the physical mixtures with respect to those of the complexes. The crystalline complexes adopted a head to head channel-type and cage conformation for alpha-CD/MBT and alpha-CD/MBI inclusion complexes, respectively.