What is a coating?
A coating is a covering that is applied to the surface of an object. The purpose of applying the coating may be decorative, functional, or both. Coatings are ubiquitous and can be found on walls, furniture, on all sorts of wires and printed circuits, the outside of houses and cars, and much more. In addition, the decorative duties of coatings span quite a broad spectrum.
Decorative coatings are mainly used for their color, texture or other visual property. Functional coatings are applied to change the surface properties of the substrate, such as adhesion, wettability, corrosion resistance, wear resistance and more. In some cases, the coating adds an entirely new property such as a magnetic response or electrical conductivity and forms an essential part of the finished product.
Coatings may be used in various processes, that are roughly divided into: vapor deposition, spraying, chemical and electrochemical techniques, roll-to-roll coating processes and other, less prominent techniques.
What is graphene?
Graphene is a two dimensional layer of carbon atoms, arranged in the form of a honeycomb lattice. It is touted as a “miracle material” because it is endowed with an abundance of astonishing traits - this thin, one atom thick substance is the lightest, strongest, thinnest material known to man, as well as the best heat and electricity conductor ever discovered - and the list does not end there. Graphene is the subject of relentless research and is thought to be able to revolutionize whole industries, as researchers work on many different kinds of graphene-based materials - each one with unique qualities and purpose.
Graphene for coatings
The vast selection of extraordinary properties that graphene possesses can open the door to many interesting types of coatings, paints, inks and more. Graphene's high resistivity can make for durable coatings that do not crack and are resistant to water and oil; its excellent electrical and thermal conductivity can be used to make various conductive paints, and a strong barrier effect can contribute to extraordinary anti-oxidant, scratch-resistant and anti-UVA coatings.
Graphene enables a wide array of functional coatings and paints, for many possible applications. Among these can be high performance adhesives enabled by graphene's high adhesion property, anti-bacterial coatings, solar paints (capable of absorbing solar energy and transmitting it), paints that provide isolation for houses, anti-rust coatings, anti-fog paints and UV ray blockers, non-stick coatings for various domestic applications (like frying pans and countertops) and even a much-hyped possibility (currently under scientific examination) of a coating that turns a regular wall into a screen.
Commercial activity
Graphene-enhanced products are yet to reach widespread commercialization. Nonetheless, given graphene’s impressive array of properties and the vigorous R&D that is taking place, graphene-enhanced coatings should not be too far away.
The Sixth Element Materials, a Chinese company that focuses on R&D, mass production and sales of graphene and related materials, showcased its graphene-zinc anti-corrosion primer used for offshore wind power tower, that can come at a competitive price compared with zinc rich epoxy primer.
Garmor, the University of Central Florida spin-off formed to develop a new graphene oxide flakes production process, has developed graphene oxide-based coatings useful for limiting UV radiation damage to sensors and polymers. Garmor's transparent GO-films are reportedly derived from a commercially-viable and scalable process that can be readily implemented with minimal constraints.
Four layers of GO coating on polycarbonate
The Spain-based Graphenano announced the launch of a graphene-based series of paints and coatings called Graphenstone in 2014. These are said to be very strong and also acts as a protective layer against environmental damage. Graphenstone is made from a graphene powder and limestone powder.
The British Electro Conductive Products released a sprayable transparent conductive coating based on a CNT and graphene platelets (GNP) hybrid material. TBA are targeting the food, electronics, pharmaceuticals and petrochemicals markets.The new ATEX-compliant product is available as a clear, anti-static aerosol, and it should also be available as bulk paint. Its application will safeguard electronic equipment used in explosive environments and bring it up to European standards.
Further reading
The latest graphene coating news:
Iceni Labs enters MoU with 2DM to develop graphene-based products for the defense, automotive and aerospace markets
Iceni Labs, a spin-out from Imperial College London, has signed a Memorandum of Understanding (MoU) with Singapore’s 2D Materials (2DM) that will see the companies combine their respective expertise to develop and market graphene-based products for the defense, automotive and aerospace markets in Europe, North America and the Middle East.
Iceni Labs, a spin-out from Imperial College London, aims to exploit the properties of graphene for devices aimed at the defense market. 2DM manufactures graphene as an additive to enhance the properties of many industrial materials. The MoU will explore the potential to use 2DM’s graphene as an industrial additive to enhance the properties of Iceni Labs-developed industrial products including microphones, weapons optics devices and coatings.
Directa Plus' graphene coatings used in two collections displayed at the Milan Design Week
Directa Plus has announced that its new G+ graphene coatings are being used in two collections at the Milan Design Week. During the event, designers, architects, creatives, producers and brands in furniture and upholstery and interior design show their new products and creations.
The graphene product is being displayed by two Italian companies: Plinio il Giovane, a central Milan based producer of high-end furniture and upholstery, and Danese Milano, a subsidiary of lighting company Artemide. The G+ coating has been used for Plinio il Giovane’s chairs and sofas and Danese Milano’s desk pad.
Graphene oxide barrier to protect electronics, artwork and solar cells
Curtin University researchers have recently shown that applying a thin (and of course, invisible) layer of graphene oxide to silicon forms an impermeable barrier, which could be used to protect artwork, prevent corrosion of metals, and produce higher efficiency solar cells.
Lead author, Dr. Nadim Darwish from Curtin’s School of Molecular Life Sciences, said while protective layers on silicon were already used as an efficiency enhancer in devices such as solar cells and microchips, the procedure for forming these protective coatings was complicated and required highly specialized fabrication laboratories.
First commercial contract for water filtration membranes enhanced with graphene oxide
UK's G2O Water Technologies has reported securing its first commercial contract for the enhancement of water filtration membranes with graphene oxide.
The Company explains that the advantages of using graphene oxide lie in the enhancement of membrane performance, as it mitigates the effects of fouling – one of the biggest challenges operators of membrane-based water filtration systems face. With a coating of graphene oxide, successfully developed and piloted by the company in the northwest of England in collaboration with Hydrasyst Limited, operators can improve operational efficiency, reduce energy consumption and decrease chemical usage. It is anticipated that this will extend the lifetime of the membranes, as well as significantly reduce the cost and environmental impact of water treatment.
New graphene-based coating developed for the protection of paintings
A team of researchers from the Institute of Chemical Engineering Sciences of Foundation for Research and Technology-Hellas (FORTH/ ICE-HT), the Department of Chemical Engineering of the University of Patras, and the Center for Colloid and Surface Science (CSGI) of the University of Florence, led by Professor Costas Galiotis, set out to use 'graphene veils' for the protection of paintings against environmental degradation.
The exposure of colors used in artworks to ultraviolet (UV) and visible light in the presence of oxidizing agents, triggers color degradation, fading and yellowing. These degradation mechanisms can lead to irreversible alteration of artworks, which consist of a valuable heritage for humankind. Currently used protective varnishes and coatings are often problematic, as their removal requires the use of solvents, which can adversely affect the underlying work surface.