Stacking Graphene Makes It More Slippery

A team of scientists from the US National Institute of Standards and Technology (NIST) say that graphene has the tendency to become more slippery when stacked. In a single-sheet configuration, the material usually slows down objects.

The NIST group compares the effect a single layer of graphene has on objects rolling on top of it to the slowing down of cars on hot pavement. In the latter case, friction increases due to the fact that the surface of pavement becomes more fluid.

The exact same thing happens on the surface of single-atom-thick graphene sheets. However, the effect almost disappears when multiple sheets of the hexagonal, 2D carbon compound are stacked on top of each other.

This idea has not yet been tested experimentally, since the process would be extremely complex. However, the new theoretical study developed by the NIST group appears solid enough on its own. What researchers did was basically create a software capable of quantifying the material's friction.

Since the first paper describing the production of graphene was published in 2004, researchers have been continuously finding out more and more details about the material. Applications range from uses in electronic equipment to lubricant for nanoscale robots and catalyst for solar cells.

In fact, it could be that graphene will replace silicon in the future as the basic material used in electronic circuits. Its chemical and physical properties are amazing, and they can replicate everything silicon can do with increased efficiency.

“I don't think anyone expects graphene to behave like a surface of a three-dimensional material, but our simulation for the first time explains the differences at an atomic scale,” NIST postdoctoral researcher Alex Smolyanitsky explains. He is a coauthor of the new paper describing the study.

”If people want to use graphene as a solid-state lubricant or even as a part of flexible electrodes, this is important work,” adds the scientist, who was also the author of the NIST modeling algorithms.

Details of the research appear in a paper entitled “Effect of elastic deformation on frictional properties of few-layer graphene,” which was published in the January 9 online issue of Physical Review B.