Figure 1. Preparation of graphene dispersion
Figure 2. Corrosion resistance and wear resistance of graphene-modified composite coatings
Figure 3. Graphene hybrid structure and electron microscopy; Hybrid composite coating corrosion protection mechanism and corrosion resistance
Figure 4. (a) Blank water-based coating (b) Conductive polymer composite coating (c) Local current density distribution at defects in graphene hybrid composite coating
Graphene has unique nanosheet structure and excellent conductivity, mechanical properties and barrier properties, and has been a hotspot in the field of composite materials (coatings) in recent years.However, due to its high specific surface area and interlayer interaction, Making it easy to agglomerate in the polymer resin matrix, can not give full play to the excellent properties of single or few layers of graphene, limiting its application in many fields.
Chinese Academy of Sciences, Ningbo Institute of Materials Technology and Engineering Marine Functional Materials team researcher Wang Liping and Zhao Haichao organic functional coating group, dedicated to graphene chemical and physical modification, and graphene multi-functional composite coating preparation and research. Based on the π-π interaction between graphene and conductive polymer, the team prepared soluble conductive polymer through controlled polymerization and combined with ultrasonic dispersion to achieve the liquid phase separation of graphene. The dispersion concentration of conventional graphene in organic solvent reached 5mg / mL, the average thickness of the graphene sheet after stripping is in the range of 2-3nm (Figure 1) .By the passivation effect of the conductive polymer on the coating substrate and the shielding and self-lubricating effect of the graphene two-dimensional nanosheet structure, Only add a small amount of peeled graphene (0.5%) epoxy composite coating corrosion resistance, lubricity and wear resistance have been greatly improved. Relevant work published in the Carbon, and apply for national invention patents.
The hydrophobicity of graphene makes it difficult to disperse it in water and aqueous resin.The team prepared water-soluble conductive polymer latex nanoparticles as an intercalation agent for graphene by microemulsion polymerization (Figure 3) The two-dimensional nanosheets are dispersed stably in water-based resin. The prepared water-based epoxy coating can reduce the corrosion due to the formation of physical barrier layer in graphene to prolong the diffusion path of corrosive medium. The conductive polymer can make the metal surface dense Passivating the film, inhibiting corrosion, synergistically enhancing the corrosion resistance of the composite coating and demonstrating self-healing of the coating by Scanning Vibration Electrode Technique (SVET) (Figure 4) The work was published on ACS Applied Material & Interfaces.
The research was supported by the Chinese Academy of Sciences's "Hundred Talents Program", the CAS Frontier Scientific Research Program, graphene major science and technology projects in Zhejiang Province and Zhejiang Provincial Natural Science Foundation.
