Wear and corrosion resistance of self-healing epoxy coatings filled by polydopamine-modified graphene oxide assembly of polysulfone double-walled microcapsules

Abstract

In order to obtain a microcapsule self-healing coating with outstanding wear and corrosion resistance, a novel double-walled microcapsule filling epoxy resin (EP) coating was fabricated by assembling graphene oxide (GO) onto the outer shell layer of polysulfone (PSF) through polydopamine (PDA) modification. The surface of the as-prepared double-walled microcapsules was rough with a particle size of 60–70 μm and a wall thickness of 2–3 μm. With enhanced dispersion and compatibility, the double-walled microcapsule filling composite coating showed enhanced mechanical performance and thermal stability. The average friction coefficient and wear rate of the EP coating filled with 10.0 wt% of microcapsules were 37.0 % and 75.2 % lower than those of the pure EP coating, respectively. The impedance value and low-frequency impedance modulus of the coating were 17.5 and 10.7 times higher than those of pure EP after 7 d of immersion, respectively. And the scratch healing was more obvious with enhanced surface hydrophobicity after 72 h of self-repair. The excellent wear and corrosion resistance of the self-healing EP coating was attributed to the synergistic wear and corrosion resistance mechanism of the double-walled microcapsules.