This image shows a graphene nanoribbon anchored at the tip of an atomic force microscope being dragged over a gold surface. Image: University of Basel, Department of Physics.An international team of researchers has discovered that the one atom-thick sheets of carbon known as graphene offer a great deal of potential for use as a coating for machine components and as electronic switches. This comes from their study of the lubricity of graphene on the nanometer scale: since it produces almost no friction at all, graphene could drastically reduce energy loss in machines when used as a coating. The researchers report their findings in Science.
In the future, graphene could be used as an extremely thin coating, resulting in almost zero energy loss between mechanical parts. This is based on the exceptionally high lubricity – or superlubricity – of graphene. Applying this property to mechanical and electromechanical devices would not only improve energy efficiency but also considerably extend the service life of the equipment.
Led by Ernst Meyer at the University of Basel in Switzerland, the researchers studied the superlubricity of graphene using a two-pronged approach that combined experimentation and computation. To do this, they anchored two-dimensional strips of graphene – so-called graphene nanoribbons – to the tip of an atomic force microscope and dragged them across a gold surface. They also used computer modelling to investigate the interactions between the surfaces as they moved across one another.
The experiments revealed almost perfect, frictionless movement: graphene nanoribbons with a width of 5–50nm could be moved using extremely small forces (2 to 200 piconewtons). There was also a high degree of consistency between the experimental observations and the computer simulation.
The only discrepancy between the model and the experiments appeared when the distance between the measuring tip and the gold surface was greater than 5nm. This is probably because the edges of the graphene nanoribbons are saturated with hydrogen, which was not accounted for in the simulations.
"Our results help us to better understand the manipulation of chemicals at the nano level and pave the way for creating frictionless coatings," write the researchers.
This story is adapted from material from the University of Basel, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.