High protection performance based on corrosion media-consumption and barrier properties of the supramolecular polymer reinforced graphene oxide composite coatings

Two-dimensional (2D) lamellar materials based protective coatings demonstrate a highly durable barrier property for anticorrosion applications. However, inevitable inhomogeneity and free spaces in coating induce the permeation and diffusion of water and oxygen molecules which accelerates the corrosion rate while reduces the protection life. The combination of physical barrier of 2D lamellar material and water-consuming property of polymers is expected to show synergistic effect to solve this problem. Herein, we report the preparation of a novel graphene/supramolecular polymer material (PEI-PAA-GO) as coating, based on 2D-lamellar graphene oxide (GO) with branched poly (ethylene imine) (PEI)/poly (acrylic acid) (PAA). Optimal combination of graphene barrier effect with the water-consumption of the supramolecular polymer contribute to the exceptional corrosion resistance and endow the coating with impedance modulus up to 8.0 × 103 Ω cm2 during the water-consumption process, 4 folds higher than that of pure PEI/PAA coating. Water uptake ratio also decreases from ~25% to ~15%, which efficiently prevents the coating from swelling. The PEI/PAA supramolecular polymer imparts the coating with self-repairing ability and its high repairing efficiency of 143.75 Ω h−1 within 24 h further enhances its protective capability. The corrosion current decreases to 10–9 A cm−2 upon 360 h protection in 3.5 wt% NaCl solution, superior to other works. The PEI-PAA-GO with synergistic protection mechanism decreases the corrosion rate remarkably and exhibits exceptional performance for variety of anticorrosion practical applications.