Enhancing corrosion and wear resistance performances of epoxy coating with incorporation of solution processable gallocyanine-functionalized rGO

Abstract

The dispersion of reduced graphene oxide (rGO) nanosheets in organic solvents and its compatibility in polymer matrix is crucial to enhancing the anticorrosion and anti-wear performance of the formed composites. Herein, we developed a new exfoliation method using aromatic gallocyanine as dispersant via π-π interaction between rGO and gallocyanine molecules with the assistance of ball milling, and successfully obtained a well-dispersed rGO ethanol solution. Results obtained from transmission electron microscopy (TEM), Raman spectroscopy, UV–vis absorbance spectroscopy (UV-VIS) and scanning probe microscopy (SPM) reveal the successful exfoliation of rGO nanosheets. Furthermore, the corrosion and wear resistance of g-rGO/EP coating were systematically evaluated by electrochemical measurements, tribological tests, scanning electron microscope (SEM), laser scanning confocal microscopy (LSCM), and Raman spectroscopy. Results demonstrated that gallocyanine-dispersed rGO nanosheets endowed resin matrix with outstanding long-term anticorrosive and excellent anti-wear properties compared to pure epoxy resin (EP), whose impedance at low-frequency limit kept 4.789 × 10⁹ Ω cm² after immersing 75 days in 3.5 wt% NaCl and wear rate showed a decrease of nearly 74.8 %. The remarkable properties can be ascribed to the enhanced multi-layer barrier property and lubrication effect caused by g-rGO.