Molecular dynamics simulation and experimental study of the rheological performance of graphene lubricant oil

Abstract

The microscopic molecular motion behavior between graphene and the liquid lubricant oil affects the rheological and frictional behavior of the nano-lubricant. However, the effect of graphene on the rheological behavior of industrial #3 lubricant oil has not been revealed. Thus, molecular dynamics (MD) and experimental study are used to investigate the effect of graphene concentration, size, temperature, and shear rate on the viscosity, mean square displacement (MSD), and density of graphene lubricant oil are investigated. The results show that the viscosity of GLO increases with the increase of graphene concentration and decreases with the increase of temperature (293 K–330 K). The MSD of graphene lubricant oil decreases with the increase of graphene size and increases with the increase of temperature. It is worth noting that graphene lubricant oil with 3G has the maximum value of MSD, which means the graphene has the best diffusion performance at this concentration. Compared to the base oil, the simulation and experiment viscosity values of the GOL with 3G increased by 22.9 % and 47.6 %, respectively. The GOL has the characteristics of a Newtonian fluid. This study can provide a reference for the application of graphene lubricant oil in industry.