Aqueous lubrication with poly(ethylene glycol) brushes

Abstract

Hydrophilic polymer brushes constitute a man-made approach to imitating nature's lubrication mechanisms. A polymer that has been frequently used to explore such systems is poly(ethylene glycol) (PEG). While PEG may not be the ideal solution for water-lubricated tribosystems for a number of technical reasons, this well-characterized polymer has served as an extremely useful model for the development of other polymer-brush-based lubricant approaches. This review covers the history of PEG brushes used as aqueous lubricants, including the large body of work on electrostatically attached PEG brushes, and ends with a discussion of current and future research directions that build upon the knowledge gained over a decade and a half of PEG-brush research in tribology.