Graphene as a 2D nanomaterial has been extensively researched as a new additive to improve barrier performance, reducing corrosion and extending service life. Significant uplifts in anticorrosive performance in solvent based coatings through the use of graphene nanoplatelets has previously been demonstrated, presenting new opportunities for improved protective coatings with extended service life. However, water-based coating development remains a key focus for industry formulators where there is an ongoing effort to reduce the release of volatile organics and achieve comparable anti-corrosion performance to that seen in solvent based systems. To date the, dispersion of graphene in water-based systems has been problematic, causing coating instability or requiring large amounts of surfactant. The authors report a breakthrough technology enabling easy dispersion in water-based coatings while delivering improved corrosion performance. This development provides an important step to raising waterborne coating anti-corrosion performance and extension of water-based system use.
Graphene was first isolated in 2004 by Andre Geim and Konstantin Novoselov at Manchester University. They used sticky tape to remove single layers from the surface of graphite and deposit them on a silicon wafer. The isolation of graphene was a breakthrough for which Geim and Novoselov ultimately won the 2010 Nobel prize for Physics. In its purest form, graphene possesses an unsurpassed combination of electrical, mechanical and thermal properties, which gives it the potential to replace existing materials in a wide range of applications and, in the long term, to enable new applications. Graphene's unique two-dimensional structure in the nanoplatelet form results in very high aspect ratio, high surface area materials which are particularly suited for use as multi-functional additives in paints and coatings formulations. Typical current barrier type lamella pigments used within coatings, such as glass flake and micaceous iron oxide, offer a much lower aspect ratio compared with graphene materials, which results in a reduced tortuosity factor and diffusion path length within the coating. Through the use of graphene materials, a superior diffusion path length can be achieved at much lower loading levels compared to traditional barrier additives.
