pH-Responsive Containers Based on Modified Hollow TiO₂for Active and Passive Protection of Carbon Steel

In this study, TiO 2 containers with an empty core and a mesoporous shell were successfully synthesized via hydrothermal reaction. The as-prepared TiO 2 was used as carrier to load the corrosion inhibitor 2-mercaptobenzimidazole (MBI). The outer shell of inhibitor-loaded containers was modified by a SiO 2 film, which was obtained from hydrolysis of tetraethyl orthosilicate (TEOS) and (3-aminopropyl) triethoxysilane (APTES). The structure of the TiO 2 containers was studied using X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR) spectrometry. The release behavior of the corrosion inhibitor was investigated using UV-visible spectroscopy. The corrosion protection performance of the water-based epoxy coating with modified TiO 2 containers was studied by using electrochemical impedance spectroscopy (EIS) and a scanning Kelvin probe (SKP). The coating with modified TiO 2 containers demonstrated enhanced film barrier properties compared with blank coating. Results obtained from SKP measurements confirmed active corrosion protection performance of the studied TiO 2 containers.