graphene
Graphene oxide can be used as paint for an ultra-strong, non-corrosive coatingCreative Commons

The surface of graphene, a one atom thick sheet of carbon, can be randomly decorated with oxygen to create graphene oxide: a form of graphene that can be applied as paint for a non-corrosive, ultra-strong coating.

The discovery may have a significant impact on the chemical, pharmaceutical and electronic industries.

Graphene oxide solutions can be used to paint various surfaces ranging from glass to metals to even conventional bricks, scientists from the University of Manchester have found.

After a simple chemical treatment, the resulting coatings behave like graphite in terms of chemical and thermal stability but become mechanically nearly as tough as graphene, the strongest material known to man.

The team, led by Dr Rahul Nair and Nobel laureate Sir Andre Geim, demonstrated previously that multilayer films made from graphene oxide are vacuum tight under dry conditions but, if exposed to water or its vapour, act as molecular sieves allowing passage of small molecules below a certain size. Those findings could have huge implications for water purification.

This contrasting property is due to the structure of graphene oxide films that consist of millions of small flakes stacked randomly on top of each other but leave nano-sized capillaries between them. Water molecules like to be inside these nanocapillaries and can drag small atoms and molecules along.

The new research shows that it is possible to tightly close those nanocapillaries using simple chemical treatments, which makes graphene films even stronger mechanically as well as completely impermeable to everything - whether it is gases, liquids or strong chemicals.

For example, the researchers demonstrate that glassware or copper plates covered with graphene paint can be used as containers for strongly corrosive acids.

The exceptional barrier properties of graphene paint have already attracted interest from many companies, who now collaborate with The University of Manchester on development of new protective and anti-corrosion coatings.

"Graphene paint has a good chance to become a truly revolutionary product for industries that deal with any kind of protection either from air, weather elements or corrosive chemicals. Those include, for example, medical, electronics and nuclear industry or even shipbuilding, to name but the few," Dr Nair said.

First author Dr Yang Su added: "Graphene paint can be applied to practically any material, independently of whether it's plastic, metal or even sand.

"For example, plastic films coated with graphene could be of interest for medical packaging to improve shelf life because they are less permeable to air and water vapour than conventional coatings. In addition, thin layers of graphene paint are optically transparent."

The week the BBC reported that a second £60m graphene centre was planned at the University of Manchester.

The research was published in Nature Communications.