Fabrication of microcapsules with graphene/organic hybrid shell based on Pickering emulsions for self‐healing anti‐corrosive coatings

Abstract

During the utilization of organic coatings, microcracks may arise as a result of external environmental influences and inherent aging, significantly diminishing the coating's lifespan. In this study, we employed the Pickering emulsion template method combined with interfacial polymerization to fabricate graphene oxide/polyurethane/polyaniline (GO/PU/PANI) organic–inorganic hybrid shell microcapsules utilizing isophorone diisocyanate (IPDI) as the core material. The capsules exhibited an average particle diameter of 3.11 μm and an encapsulation rate of 78.19%. Subsequently, these prepared capsules were incorporated into a photocurable resin to obtain a self‐healing corrosion‐resistant coating. Scanning electron microscopy analysis demonstrated that even with just 5% addition of microcapsules, nearly complete repair could be achieved. The tensile strength and flexural strength of the self‐healing material containing 5% microcapsules were measured at 84.8 MPa and 193 MPa respectively. These values represented only a marginal decrease in tensile strength by 2.75% and flexural strength by 5.39%, compared to the substrate without capsule addition. Remarkably, after immersing the repaired coating in a NaCl solution with a concentration of 5 wt% for up to 250 hours, the alternating current impedance value remained stable at approximately 6.9 × 105 Ω·cm2. This outstanding corrosion resistance can be attributed to synergistic effects between PANI and IPDI within the coating system, thereby expanding its potential applications under harsh conditions.