Ultra-dispersive monolayer graphene oxide as water-based lubricant additive: Preparation, characterization and lubricating mechanisms

Abstract

Although graphene oxide (GO) is deemed as an admirable lubricant additive to enhance the tribological properties of water, there remain great challenges in improving its dispersion stability and re-dispersity in water, and understanding the effects of dispersity and exfoliation degree on lubricity of GO. Herein, the functionalized GO (GO-EmimN(CN)2) with extraordinary dispersity, re-dispersity and high exfoliation degree is successfully prepared using 1-ethyl-3-methyl imidazolium dicyanamide as intercalator of multilayer graphene oxide (MGO). GO-EmimN(CN)2 as water-based lubricant additive dramatically decreases the wear rate and wear width of GCr15 steel by 74% and 40% compared to pure water, 53% and 45% to MGO respectively. Finally, lubricating mechanisms of GO-EmimN(CN)2 are determined and proposed via abundant surface analysis techniques.