Eutectic systems containing an ionic liquid and PEG200 as lubricants for silicon surfaces: Effect of the mixture’s molar ratio

•Eutectic systems (ESs) have been successfully tested as lubricants.•Frequently, the composition of the ESs is arbitrarily chosen.•The proximity of the eutectic point composition enhances the HBD-HBA interactions.•Optimal lubrication properties occur for the composition closest to the eutectic.