Preparation and Tribological Study of Functionalized Graphene–IL Nanocomposite Ultrathin Lubrication Films on Si Substrates

Nanocomposite materials based on graphene and ionic liquids (ILs) with unique and highly attractive properties have received considerable interest in various research fields, including biosensors, electrochemical sensors, and so on. Given the excellent mechanical properties and frictional properties of graphene nanosheets, nanocomposite ultrathin films composed of graphene nanosheets and ionic liquids (ILs) with excellent lubricating property are expected to possess improved comprehensive tribological performance. In the current paper, various functionalized graphene–IL nanocomposite ultrathin lubrication films on Si substrates, on the basis of the good dispersion of graphene nanosheets that were noncovalently functionalized by imidazolium-based ILs in acetone, were successfully prepared by an electrostatic adsorption method and were confirmed by several characterization techniques. Appropriate amounts of functionalized graphene nanosheets uniformly distributed on the substrate surface without overlapping greatly enhanced the load-carrying capacity of the ultrathin lubrication films, and the new nanocomposite films gave excellent micro/nanotribological properties. The novel nanocomposite films are hoped to find promising applications in the lubrication of micro/nanoelectromechanical systems (MEMS/NEMS).