The team studied the lubricity of graphene by combining experimentation and computation. They anchored graphene nanoribbons to a sharp tip and dragged them across a gold surface. Computer-based calculations were used to investigate the interactions between the surfaces as they moved across one another.
By studying the graphene nanoribbons, the researchers hope to learn about more than just the slip behaviour. Measuring the mechanical properties of the carbon-based material also makes sense because it offers potential for applications in the field of coatings and micromechanical switches. In future, electronic switches could be replaced by nanomechanical switches, which would use less energy for switching on and off than conventional transistors.
The experiments are claimed to have revealed almost perfect, frictionless movement. It is said to be possible to move graphene nanoribbons with a length of 5 to 50nm using forces of 2 to 200pN. The researchers say there is a high degree of consistency between the experimental observations and the computer simulation.
A discrepancy between the model and reality appears only at greater distances – 5nm or more - between the measuring tip and the gold surface. The researchers say this is probably because the edges of the graphene nanoribbons are saturated with hydrogen, which was not accounted for in the simulations.