Linkoping University researchers have demonstrated that graphene can be made more useful by adding hydrogen or helium.
The researchers have reported their findings in Physical Review A. In the paper, the researchers demonstrate that the van der Waals forces between atoms get affected by the addition of hydrogen at a specific concentration, causing them to repel rather than attract. Hence, the graphene sheets repel one another, causing them to float apart freely at a nano-scale distance.
In the experiment, the researchers started with two undoped graphene sheets over a silicon dioxide or silica substrate. The van der Waals attractive forces are the starting position, which make the sheets to come close towards each other. However, repulsive forces are generated due to the addition of the atomic hydrogen. The researchers noticed a similar effect when they utilized other gases, including molecular helium and hydrogen.
Graphene, a two-dimensional material with one-atom thickness, demonstrates unique properties. It is stronger when compared to diamond. The flexible, transparent material has better electrical conductivity.
The findings of the study are helpful to advance hydrogen storage for vehicle fuel applications. Repulsive forces are suitable for the production of friction-free nano-scale components such as sensors and robots for medical applications. Linkoping University developed a method to produce an individual graphene sheet by stripping it from a stack developed on a silicon carbide substrate.
Source: http://www.liu.se