Corrosion inhibition of functionalized graphene modified self-repairing anti-corrosion coating of Ningbo material

Graphene is a two-dimensional nanomaterial with good mechanical properties, high aspect ratio and excellent barrier properties. In recent years, it has received extensive attention in the field of organic corrosion protective coatings. However, due to the poor interfacial compatibility of graphene and the coated matrix resin, defects such as micropores, microcracks, and the like, and galvanic corrosion due to the high conductivity of graphene may limit its further application.

At present, most of the graphene-modified organic anti-corrosion coatings use the physical barrier of graphene to improve the passive anti-corrosion ability of the composite coating, and can not meet the long-term use requirements of the coating under complex working conditions. In response to this problem, Wang Liping, a researcher in the marine functional materials team of the Institute of Materials Technology and Engineering of the Chinese Academy of Sciences, and Liu Chengbao, a doctoral student directed by Zhao Haichao, designed a series of functionalized graphenes to solve the corrosion reaction caused by defects in the coating microdomain. The ionic liquid functionalized graphene is obtained by introducing a green corrosion inhibitor imidazolyl ionic liquid into the surface of graphene by a covalent method. The functionalized graphene can be uniformly dispersed in the aqueous resin, and has certain corrosion inhibition property, can effectively inhibit the metal corrosion reaction at the interface of the defect, and greatly enhance the protective performance of the coating (Nanoscale, 2018, 10, 8115-8124). In order to avoid the corrosion promotion caused by the contact between the graphene-metal substrate and the graphene sheet, they grafted the natural corrosion inhibitor histidine into the graphene sheet and effectively improved the charge transfer at the interface. Corrosion resistance of the coating.

In order to further explore the electrochemical reaction process and corrosion inhibition mechanism of the coating micro-defects, the researchers prepared a graphene nano-container and nano-container enhanced self-healing coating. The interaction between the cyclodextrin molecule in the nano-tank and the host-guest between the corrosion inhibitors is used to achieve the loading of the corrosion inhibitor molecules. The release process of the corrosion inhibitor in the nanocontainer exhibits pH responsiveness. Relying on the barrier properties of graphene, the nano-tank can reduce the penetration rate of the corrosive medium and enhance the passive corrosion resistance of the coating. On the other hand, when the coating produces defects, the corrosion reaction at the defect induces the release of the corrosion inhibitor in the nano-container, and the film is adsorbed at the defect in time to prevent further occurrence of the corrosion reaction, showing a certain self-repairing property. Related work has been published in ACS Applied Material & Interfaces and applied for invention patents.

The above research work was supported by the 100-member plan of the Chinese Academy of Sciences, the frontier scientific research plan of the Chinese Academy of Sciences, the pilot project of the Chinese Academy of Sciences, and the major science and technology project of graphene in Zhejiang Province.