Self-forming oriented layer slip and macroscale super-low friction of graphene

Abstract

Graphite lubrication is not effective in vacuum, and the failure mechanism is still under debate. Here, we show that graphene as two-dimensional (2D) “graphite paper” can overcome this shortcoming of graphite. Graphene exhibits stable super-low friction in a vacuum environment at the engineering scale because it can self-form a highly ordered lamellar structure on the sliding interface during the friction process owing to its unique 2D nano-effects. Experimental observation of the layer-slip phenomenon on the low-energy-state outside layers provides direct evidence to understand the lubrication mechanism of graphitic materials.