Study on self-healing and corrosion resistance behaviors of functionalized carbon dot-intercalated graphene-based waterborne epoxy coating

Abstract

Functionalized carbon dots (CDs) obtained from citric acid derivative were selected as intercalator to modify graphene and then dispersed into epoxy matrix to prepare CDs modified graphene/epoxy (CDs-G/EP) coatings. Meanwhile, their microstructure, self-healing and corrosion resistance behaviors were analyzed deeply. Structural characterizations indicated the formation of “π-π” interaction between functionalized carbon dots and graphene. By observation, the dispersion and interface compatibility of graphene were greatly enhanced by CDs. The change rules of electrochemistry results implied that the addition of 0.5 wt.% CDs-G in EP coating (CDs-G0.5 %/EP) demonstrated a superior protective property on steel, which was attributed to the physical barrier of highly dispersed graphene and the self-healing ability of CDs. After 50 days immersion, the oxygen permeability coefficient and water absorption of CDs-G0.5 %/EP coating were only 4.27 × 10−13 cm3 cm cm−2 s−1 Pa−1 and 4.4 %, respectively.