Influence of oxidized graphene nanoplatelets and [DMIM][NTf2] ionic liquid on the tribological performance of an epoxy-PTFE coating

Abstract

This work reports the tribological performance of a self-lubricating epoxy-PTFE coating modified with oxidized graphene nanoplatelets (GNPox) and 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [DMIM][NTf2] ionic liquid, alone and in combination. [DMIM][NTf2] was incorporated without encapsulation, which is shown not to hinder coating adhesion for the tested applications. Crossed cylinders tribological testing of coatings under different load conditions showed synergistic effects from the combination of GNPox and ionic liquid. The ionic liquid introduced a plasticizing effect on the binder, increasing the actual contact area and facilitating boundary-lubrication. The boundary-lubrication regime facilitated GNPox particle orientation and reduction of their abrasive behaviour, contributing to a lowered coefficient of friction.