Bao Jin

Owing to the great barrier properties, light weight and environmental friendliness, graphene-based anticorrosion coatings are considered to be promising candidates for next-generation anticorrosion materials. Recently, polydopamine has showed considerable research value and application prospects in the field of anticorrosion, and provided new opportunities for chemical modification of graphene for the enhancement of coating performance. However, the applications and mechanisms of polydopamine-modified graphene in anticorrosion coatings have not been systematically summarized. This review focuses on the application and mechanism of graphene and polydopamine-modified graphene in anticorrosion coatings. Firstly, the intrinsic barrier properties and applications of graphene in anticorrosion coatings are summarized, especially in self-healing anticorrosion coatings. Next, the properties and applications of polydopamine in the field of anticorrosion are reviewed and discussed. Moreover, the application and mechanism of polydopamine in graphene-based anticorrosion coatings are systematically reviewed, which mainly includes enhancing the intrinsic barrier properties, improving the dispersibility, modifying with functional materials, and introducing pH-responsive properties. Finally, the critical challenges and future prospects for the development of graphene-based anticorrosion coatings are discussed. This article aims to boost further development of graphene-based anticorrosion coatings to solve the anticorrosion bottleneck of equipment in harsh corrosive environments.

Charge transfer at solid-liquid interfaces is pivotal in biochemical processes, catalysis, and electrochemical devices. However, understanding the charge transfer mechanism at the nanoscale solid-liquid interface remains highly challenging. Here, we conduct ab initio molecular dynamics simulations to investigate interfacial charge transfer between water and the two most common two-dimensional materials: graphene with nonpolar C-C bonds and hexagonal boron nitride (hBN) with polar B-N bonds. It is counterintuitive to find that the charge transfer between water and hBN is approximately 1 order of magnitude higher than that between water and graphene despite the fact that graphene is semiconducting and hBN is insulating. Our further analyses attribute this phenomenon to a higher tendency of water molecules to point a hydrogen atom toward the hBN surface compared to the graphene surface, although they have similar crystallographic structures. This single hydrogen-down water configuration on the hBN surface prompts electron delocalization from hBN and facilitates electron migration to water. Moreover, the polar B-N bonds in hBN result in a strong orbital overlap between nitrogen atoms and hydrogen atoms of water. A similar charge transfer enhancement is also observed between water and two-dimensional gallium nitride (GaN) and aluminum nitride (AlN), which also own polar bonds, and a positive correlation between the charge transfer and the bond polarity is demonstrated. Further simulations indicate that the friction coefficient of water on graphene and hBN surfaces positively correlates with the amount of charge transfer. These findings suggest that materials with polar bonds like hBN can serve as promising materials for biochemical sensors and energy conversion devices.

Engineering nanocontainers with encapsulated inhibitors onto graphene has been an emerging technology for developing self-healing anticorrosion coatings. However, the loading contents of inhibitors are commonly limited by inhomogeneous nanostructures of graphene platforms. Here, we propose an activation-induced ultrathin graphene platform (UG-BP) with the homogeneous growth of polydopamine (PDA) nanocontainers encapsulated with benzotriazole (BTA). Ultrathin graphene prepared by catalytic exfoliation and etching activation provides an ideal platform with an ultrahigh specific surface area (1646.8 m²/g) and homogeneous active sites for the growth of PDA nanocontainers, which achieves a high loading content of inhibitors (40 wt %). The obtained UG-BP platform exhibits pH-sensitive corrosion inhibition effects due to its charged groups. The epoxy/UG-BP coating possesses integrated properties of enhanced mechanical properties (>94%), efficient pH-sensitive self-healing behaviors (98.5% healing efficiency over 7 days), and excellent anticorrosion performance (4.21 × 10⁹ Ω·cm² over 60 days), which stands out from previous related works. Moreover, the interfacial anticorrosion mechanism of UG-BP is revealed in detail, which can inhibit the oxidation of Fe²⁺ and promote the passivation of corrosion products by a dehydration process. This work provides a universal activation-induced strategy for developing loading-enhanced and tailor-made graphene platforms in extended smart systems and demonstrates a promising smart self-healing coating for advanced anticorrosion applications.