The preparation of linseed oil loaded graphene/polyaniline microcapsule via emulsion template method for self-healing anticorrosion coatings

Abstract

A novel kind of graphene/polyaniline hybrid microcapsules loaded with self-healing agent (linseed oil, LO) were synthesized by Pickering emulsion template method in this work. In our strategy, graphene oxide (GO) was used as Pickering emulsifier to stabilize emulsion droplet containing aniline and linseed oil. After the polymerization of aniline, graphene/polyaniline microcapsules loaded with linseed oil (LO@GO/PANI) were prepared. By adjusting GO concentration and oil-water ratio, the size of the emulsion droplet and LO@GO/PANI microcapsule can be controlled at about 15–20 µm. The successful synthesis of LO@GO/PANI microcapsules was proved by SEM, FT-IR and TGA. The unique GO/PANI hybrid shell combined the outstanding barrier property of GO and anti-corrosion function of PANI. The solvent resistance results showed that the as-prepared microcapsules possessed stronger resistance to organic solvents. A smart coating with dual functions of anti-corrosion and self-healing was prepared by dispersing the as-prepared LO@GO/PANI microcapsule in waterborne epoxy resin. As the contents of microcapsules was 10 wt%, the scratch of the coating was completely healed after 12 h observed from the microscope images. The electrochemical impedance spectroscopy (EIS) and salt spray test all verified that the incorporation of microcapsules could significantly improve the anti-corrosion performance of the water-borne coatings. After 40 days' immersion, the low frequency modulus of the composite coating was almost 2 orders of magnitude higher than that of pure epoxy coating, and no obvious corrosion product was observed after 500 h salt spray test.