Multi-walled Carbon Nanotube-Imidazolium Tosylate Ionic Liquid Lubricant

Multi-walled carbon nanotubes (MWCNTs) were added in a 0.5 wt% proportion to 1-alkyl-3-methylimidazolium room temperature ionic liquids (IL) The new IL + MWCNTs dispersions obtained by mechanical grinding were used as lubricants of the polycarbonate (PC) disc/AISI 316L stainless steel pin contact, and their tribological performance compared with that of the corresponding IL. The highest friction reduction at 0.98 N and 0.10 m s(-1), of a 54 %, was obtained when MWCNT were added to 1-ethyl-3-methylimidazolium tosylate ([EMIM]Ts). The [EMIM]Ts + MWCNT dispersion was further characterised by rheological measurements, contact angle, DSC, TGA, FTIR and Raman spectroscopies, TEM microscopy and XRD. The addition of MWCNTs increases the viscosity of the IL in a 50 % at room temperature and the wettability on the PC surface, while the IL increases the purity and alignment of the nanotubes. The variation of friction coefficient was determined under variable sliding velocity conditions. The higher friction reduction for [EMIM]Ts + MWCNT with respect to [EMIM]Ts is observed for sliding velocities higher than 0.075 m s(-1). Under the experimental conditions, the surface damage on the PC and AISI 316L surfaces was negligible.