Ionic liquids (ILs), a class of low-melting-point organic salts, are
promising candidates as high performance “green” lubricants due
to their negligibly low vapour pressure, excellent thermal stability,
electrical conductivity and controllable physical and chemical
properties. ILs are thus proposed to solve some of the most dif-
ficult lubrication problems occurring in a number of engineering
applications (Palacio & Bhushan, 2010). For example, micro electrical
mechanical systems (MEMS) require low-viscosity lubricants