Influence of the micromorphology of reduced graphene oxide sheets on lubrication properties as a lubrication additive

The microstructures of graphene sheets have been widely researched, but few studies have been conducted on the influence of their micromorphology on lubrication properties. In this paper, the lubrication properties of three types of reduced graphene oxide sheets with different micromorphologies—regular edges (RG), irregular edges (ir-RG), and both irregular edges and wrinkles (ir-RWG)—were investigated. RG lubricant has the best lubrication properties and its friction coefficient and wear-scar depth remarkably decrease to 27.9 and 14.1% of that of base oil, respectively, whereas ir-RWG has the worst. The morphological regularity of the graphene sheets has a direct influence on their lubricant properties. The more regular, the better the properties. The results provide an efficient method for researchers to prepare suitable graphene sheets as lubrication additives.