New Single-Walled Carbon Nanotubes-Ionic Liquid Lubricant. Application to Polycarbonate-Stainless Steel Sliding Contact

Single-walled carbon nanotubes (NTs) were added in a 0.5 wt% proportion to the room temperature ionic liquid (IL) 1-octyl, 3-methylimidazolium chloride ([OMIM]Cl). The [OMIM]Cl + NT mixtures obtained by mechanical grinding in an agate mortar ([OMIM]Cl + NT(g)) or by mechanical grinding and ultrasound dispersion ([OMIM]Cl + NT(g + us)) were used as lubricants of the polycarbonate (PC) disc/AISI 316L stainless steel pin contact. When the [OMIM]Cl + NT(g + us) dispersion is used, a negligible wear rate and a friction coefficient reduction of a 66% with respect to neat IL, and of a 50% with respect to [OMIM]Cl + NT(g), is achieved. Results are discussed on the basis of DSC, TGA, Raman spectroscopy, TEM microscopy, XRD, XPS and surface topography analysis.