title: Ordering layers of [bmim][PF6] ionic liquid on graphite surfaces: molecular dynamics simulation.
abstract: Microscopic structures of room temperature ionic liquid (IL) [bmim][PF6] on hydrophobic graphite surfaces have been studied in detail by molecular dynamics simulation. It is clearly shown that both the mass and electron densities of the surface adsorbed ionic liquid are oscillatory, and the first peak adjacent to the graphite surface is considerably higher than others, corresponding to a solidlike IL bottom layer of 6 angstroms thick. Three IL layers are indicated between the graphite surface and the inner bulk IL liquid. The individually simulated properties of single-, double-, and triple-IL layers on the graphite surface are very similar to those of the layers between the graphite surface and the bulk liquid, indicating an insignificant effect of vapor-IL interface on the ordered IL layers. The simulation also indicates that the imidazolium ring and butyl tail of the cation (bmim+) of the IL bottom layer lie flat on the graphite surface.
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800, People's Republic of China.
authors.forename: Sha
authors.initials: S
authors.lastname: Maolin
authors.forename: Zhang
authors.initials: Z
authors.lastname: Fuchun
authors.forename: Wu
authors.initials: W
authors.lastname: Guozhong
authors.forename: Fang
authors.initials: F
authors.lastname: Haiping
authors.forename: Wang
authors.initials: W
authors.lastname: Chunlei
authors.forename: Chen
authors.initials: C
authors.lastname: Shimou
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yi
authors.forename: Hu
authors.initials: H
authors.lastname: Jun