Hydroxyl-terminated ionic liquids functionalized graphene oxide with good dispersion and lubrication function

Multilayer graphene oxide (MGO) as water-based lubricant additive has promising prospect, however, its dispersity and lubricity still need to be enhanced for the practical application. Herein, hydroxyl-terminated ionic liquids coupling agents (ILCAs) are used for functionalizing MGO, the as-prepared functionalized GO (ILCAs-GO) shows better dispersity in water and better lubricity than pristine MGO. Surface analysis reveals ILCAs-GO sheets can continuously deposit on the worn surface during the friction process via the electrostatic adsorption of ILCAs-GO and metal ions. These continuously deposited sheets can heal the damaged transfer film and increase the wettability of water on friction pairs, meaning the self-healing and self-wetting functions are realized which provides the effective protection for the tribo-pairs thus reducing wear of materials.