The distinguished long-term friction reduction and anti-wear functions of amphipathic carbon dots originated from lauryl gallate

Abstract

The tribolgical performance of amphipathic carbon dots (A-CDs) originated from lauryl gallate as lubricant additives of polyethylene glycol (PEG200) was investigated in detail under the ball-on-disk reciprocating slide mode and steel/steel contact. The A-CDs exhibited distinguished long-term friction reduction and wear resistance functions under specific conditions. Typically, 2 wt% of A-CDs made the average friction coefficient and wear volume of wear track lubricated with PEG200 reduce by 51.4% and 84.4%, respectively, under the mild load of 40 N and long duration of 200 min. The worn surface analyses demonstrated that the A-CDs could be uninterruptedly deposited and smeared onto the contact areas of friction pairs, which induced the gradually formation of compact boundary lubrication films. Under the mild load, the homogeneous lubrication films were thick and robust enough to absolutely avoid the direct collisions of asperities on the sliding interfaces, well accounting for the impressive long-term friction-reducing and anti-wear abilities of A-CDs. The A-CDs offer great application potential in the field of lubricant additives due to their high lubricating performance, long service life and environmentally friendliness.