Researchers dynamically change friction in graphene

According to University of Illinois Urbana-Champaign researchers led by Professor Rosa Espinosa-Marcel of the Department of Civil and Environmental Engineering, friction on the surface of graphene can be dynamically adjusted using external electric fields. The work is extensive Paper„Dynamic friction at graphene interface using field effect”, published on September 19, 2023 in the journal Natural communication.

Friction plays an important role in natural and engineered systems, dictating the behavior of sliding contacts, affecting the wear of materials, and influencing the flow of fluids across surfaces, among other effects. Friction can be controlled passively by selecting design elements, for example material and hardness.

However, a more recent trend is to explore systems that can dynamically tune the friction response in situ, particularly where micro- and nanoscale devices are becoming more common. One of the most promising ways to achieve friction control is external electric fields, which can modify the properties of lubricant and material surfaces and the interactions between them.

„Innovative approaches to the design of interacting surfaces are necessary to advance the state of the art, and 2D materials are a new and better choice based on their high mechanical strength and chemical and thermal stability,” they write.

Graphene is a 2D form of carbon and is sometimes hailed as a „miracle material” due to its unique and extraordinary properties. Surfaces coated in graphene films typically exhibit very low friction, but the new results demonstrate that friction on graphene-coated surfaces can be „turned on” by exposing the surface to an electric field under the right conditions. The system can be controlled in this high-friction state before switching back to low-friction, all without the use of large electrical biases between the contacting surfaces.

„This work will have an impact on reducing energy consumption in nano- and micro-electromechanical systems, allowing dynamic control of friction and mitigating advanced wear and corrosion of sliding surfaces when direct bias is applied,” said Espinosa-Marcel.