Donato, Mariana T.Caetano, Fernando J. P.Colaco, RogérioBranco, Luís C.Saramago, Benilde2022-01-202022-01-202020-05-262365-6549http://hdl.handle.net/10400.2/11659New ionic liquids (ILs) based on picolinium, [C6-x-pic][TfO] where x=2, 3 and 4, were successfully synthesized using microwave process. The performance of these ILs as additives to model lubricant oil PEG200 was evaluated and compared with that of other ILs sharing the same hydrophobic anion, using the tribological pair steel sphere/Si surface. [C6-4-pic][TfO] was the most efficient additive, which may be attributed to the symmetry of the cation leading to an ordered adsorbed layer.engIonic liquidsLubricationAdditivesMicrowave synthesisSiliconjournal article10.1002/slct.202000613