Mussel-inspired preparation of dispersible mica nanosheets for waterborne epoxy coatings with reinforced anticorrosive performance

Abstract

Mica is a low-cost, naturally layered material with superior insulation, high-temperature resistance, acid and alkali resistance, but the preparation of its nanosheets on a large scale and their compatibility with resin are still to be solved. In this work, hydroxyl-functionalized mica nanosheets (MNs) were prepared by the introduction of plasma treatment with a yield of 6.695 %. Inspired by mussels, natural tannic acid (TA) was chosen to modify MNs via the interaction of catechol groups with OH to prepare functionalized MNs (MNs@TA). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) proved the successful preparation of TA-modified MNs. The obtained MNs@TA exhibited good dispersion in solvent and waterborne epoxy (WEP) coating, enhancing the compatibility with WEP resin. In addition, the MNs@TA/WEP composite coatings were used on Q235 carbon steel, and their corrosion protection performance and mechanism were investigated by electrochemical impedance spectroscopy (EIS), ultra-depth three-dimensional microscope, and energy dispersive spectrometer (EDS). The results illustrated that the incorporation of 0.5 wt% MNs@TA significantly improved the anticorrosive performance of the WEP coating via enhanced barrier properties.