A review of ionic liquid lubricants

Anthony E. Somers, Patrick C. Howlett, Douglas R. MacFarlane, Maria Forsyth

Research output: Contribution to journalReview ArticleResearchpeer-review

515 Citations (Scopus)


Due to ever increasing demands on lubricants, such as increased service intervals, reduced volumes and reduced emissions, there is a need to develop new lubricants and improved wear additives. Ionic liquids (ILs) are room temperature molten salts that have recently been shown to offer many advantages in this area. The application of ILs as lubricants in a diverse range of systems has found that these materials can show remarkable protection against wear and significantly reduce friction in the neat state. Recently, some researchers have shown that a small family of ILs can also be incorporated into non-polar base oils, replacing traditional anti-wear additives, with excellent performance of the neat IL being maintained. ILs consist of large asymmetrical ions that may readily adsorb onto a metal surface and produce a thin, protective film under boundary lubrication conditions. Under extreme pressure conditions, certain IL compounds can also react to form a protective tribofilm, in particular when fluorine, phosphorus or boron atoms are present in the constituent ions.

Original languageEnglish
Pages (from-to)3-21
Number of pages19
Issue number1
Publication statusPublished - 1 Mar 2013


  • Ionic liquids
  • Lubricant
  • Lubricants additives
  • Miscibility
  • Surface characterization
  • Surface interactions
  • Wear results

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