Cu nanoparticles decorated WS(2) nanosheets as a lubricant additive for enhanced tribological performance

Tungsten disulfide–polydopamine–copper (WS(2)–PDA–Cu) nanocomposites were first prepared by a green and effective biomimetic strategy and then used as a lubricant additive in polyalkylene glycol (PAG). The biomimetic strategy is inspired by the adhesive proteins in mussels. WS(2) nanosheets were decorated by uniformly dispersed Cu nanoparticles (Cu NPs). The WS(2)–PDA–Cu nanocomposites with good dispersion stability, showed better friction reducing and anti-wear properties than WS(2), Cu NPs and WS(2)–Cu dispersed in PAG base oil. The average friction coefficient and wear volume were reduced by 33.56% and 97.95%, respectively, at 150 °C under a load of 100 N for the optimal concentration of 0.9 wt%. The lubrication mechanism was discussed.