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 polycarbonateFour 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

Latest Graphene coating news

Graphene-enhanced anti-corrosion system deployed in bridges and wind power towers across China

Nov 13, 2017

China-based The Sixth Element Materials launched its graphene-zinc anti-corrosion primer back in 2015 together with his partner Toppen Technology, and the company has since performed extensive testing. TSE updates us that the material has now been deployed in China and has been used to cover several bridges and wind-turbines steel towers.

Anti-corrosion 2k-graphene-epoxy coating in China (TSE)

The Sixth Element graphene type SE1132 is added to Toppens 2k-epoxy primer system. TSE says that by adding 1% of graphene, one could reduce the zinc content in current anti-corrosion coatings from ~80% to 25%, and the the corrosion protection time is doubled. Reducing the zinc also means that this solution is less polluting. The main cost savings comes from the prolonged coating life which means that the time between coating renewal (which requires a lot of labor) is doubled.

Two projects demonstrate how metal-oxide coatings influence graphene

Nov 07, 2017

Two interesting projects focused on coating single-layer graphene with metal-oxide nanolayers were presented at the latest Thin Films and Coating Technologies for Science and Industry event in the UK. Researchers from Cranfield University, UK, together with collaborators from University of Cambridge and the Centre for Process Innovation (CPI), applied alumina to form a composite barrier layer, while a team from Imperial College London, UK, used the unique properties of strontium titanate to fabricate a tuneable capacitor.

The researchers of the first project explained that in theory, graphene should represent an ideal ultrathin barrier layer, as the pores between carbon atoms are smaller even than the radius of a helium atom. In practice, however, crystal boundaries and missing atoms allow vapor to permeate through the material, and the weak van der Waals bonds between planes mean that even stacks of multiple graphene layers can be penetrated. The solution reported by the team is to take a graphene monolayer formed by CVD, and to then use atomic layer deposition (ALD) to coat it with a 25–50 nm thick layer of alumina. Achieving conformal coatings on single-layer graphene is known to be difficult due to the material’s strong hydrophobicity.

Graphene Batteries Market Report

Haydale and Imagine IM sign agreement to establish graphene-based conductive coatings capability in the US

Oct 30, 2017

Haydale logoUK's Haydale and Australia-based Imagine Intelligent Materials have signed a strategic agreement to establish a graphene-based conductive coatings capability in North America. According to the agreement, Haydale is to acquire exclusive license to Imagine IM’s “Plant In A Box” graphene processing technology and establish US supply chain for graphene-based conductive coatings that are designed for the global geosynthetics market. Haydale will also import inventory of imgne X3 to support planned field trials and early adopter orders.

The companies state that the signing of a Letter of Intent (LOI) between them marks the first step in establishing a strategic collaboration. In parallel, Haydale has issued a Purchase Order to Imagine IM for a quantity of Imgne X3 that will be sufficient to enable 50,000m2 of conductive geotextile to be manufactured. This will ensure that there is available supply in the US ahead of the commissioning of a full-scale plant at Haydale’s manufacturing facility in Greer, SC.

Dotz Nano enters MoU with Colorplastic to develop GQDs-enhanced polymers and surface modificants

Oct 12, 2017

Dotz Nano, a nano-technology company focusing on the development, manufacture, and commercialization of graphene quantum dots (GQDs), recently announced the signing of a non-binding and non-exclusive MoU with Colorplastic, a polymer compounder located in Switzerland for the implementation of GQDs into the polymer and surface modificant market. The GQDs would be used in automotive plastics and anti-counterfeiting/brand protection applications.

The MoU calls for a 6-month pilot project in which GQDs will be supplied by Dotz to Colorplastic for integration into their products for use in the polymers and surface treatment being commercialized by Colorplastic for use by OEMs. The scope of the pilot is to be defined by the parties, but is to cover the technological development and adaptation of GQDs to Colorplastic's products, including production runs for validating commercial scale. The pilot can be extended an additional 3-months by mutual agreement if needed.

Graphene-wrapped nanocrystals may open door toward next-gen fuel cells

Sep 18, 2017

Researchers at the Department of Energy’s Lawrence Berkeley National Laboratory have developed a mix of metal nanocrystals wrapped in graphene that may open the door to the creation of a new type of fuel cell by enabling enhanced hydrogen storage properties.

Graphene-Wrapped Nanocrystals Make Inroads Toward Next-Gen Fuel Cellsultrathin oxide layer (oxygen atoms shown in red) coating graphene-wrapped magnesium nanoparticles (orange) still allows in hydrogen atoms (blue) for hydrogen storage applications

The team studied how graphene can be used as both selective shielding, as well as a performance increasing factor in terms of hydrogen storage. The study drew upon a range of Lab expertise and capabilities to synthesize and coat the magnesium crystals, which measure only 3-4 nanometers (billionths of a meter) across; study their nanoscale chemical composition with X-rays; and develop computer simulations and supporting theories to better understand how the crystals and their carbon coating function together.

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