title: Water adsorption and desorption on ultra-low friction sulfur-doped hydrogenated carbon films.
abstract: Water adsorption on hydrogenated carbon film surfaces can drastically affect friction behaviour. In this work, we investigate water adsorption and desorption properties of sulfur-doped hydrogenated films, which we have observed to retain ultra-low friction properties of hydrogenated carbon films in humid air. Water adsorption studies using a quartz crystal microbalance show that there is an almost threefold reduction in equilibrium water coverage at room temperature on hydrogenated carbon films doped with 5 at.% sulfur. Thermal desorption studies indicate that sulfur doping weakens the binding of water molecules on hydrogenated carbon film surfaces.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, 2220 N Campus Dr., Evanston, IL 60208, USA.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Freyman
authors.forename: Bo
authors.initials: B
authors.lastname: Zhao
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Chen
authors.forename: Yip-Wah
authors.initials: YW
authors.lastname: Chung