Molecular dynamics simulations of the interaction between graphene and lubricating oil molecules

Abstract

The microscopic interaction between graphene and liquid lubricating oil molecules significantly affects the rheological and tribological properties of the solid-liquid lubricating system. In this study, the interaction between graphene and six kinds of alkane oil droplets with different chain lengths was investigated by molecular dynamics simulations. Interaction energy, atomic concentration distribution, mean square distribution, curvature, centroid, and inclination angle were used to quantitatively describe the effect of interaction differences on lubricating performance. The results demonstrated that with the increase of the carbon chain length, the alkane molecules transformed from a spherical oil droplet model to an ordered layered structure. At the same time, the interaction energy and the angle with the Z coordinate axis were further increased. The self-diffusion movement and the degree of molecular bending were reduced during the interaction, indicating that long-chain alkane molecules interact strongly with graphene, and a dense bilayer adsorption film was formed by horizontal adsorption on the surface of graphene, thus exerting a good lubricating effect. In addition, it was found that the increase in temperature was beneficial to the occurrence of the adsorption process, but high temperature is not conducive to the stable adsorption of alkane molecules on the surface of graphene.

Amide/Amino-Based Functional Additives for Lubricants: Structure, Antimicrobial Activity and Wear Resistance

“…They affect the resistance of lubricants to seizure and wear processes and have a particular influence on additive changes during tribological processes [24,25]. The interactions that occur between the steel components of a friction junction when the base oil comes into contact with different additives were evaluated [26].The influence of lubricity additives added to paraffin oil on the tribological properties of the sialon-cast iron system was evaluated [27], and tribological transformations of the additive during the friction and wear process [28][29][30]. The effect the additive particles adsorbing on the thickener particles had on the tribological properties was evaluated [31], and the role of multifunctional additives in the friction process using bentonite-thickened grease [32].…”