title: Effect of π-π+ stacking on the layering of ionic liquids confined to an amorphous carbon surface.
abstract: In the current paper, AFM studies were conducted on nanometer-thick ionic liquids (ILs) confined to an amorphous carbon (AC) surface, which is critical to the design of the next-generation media lubricant for hard disk drives (HDDs). The results indicated that the existence of the delocalized ring in the cation is critical to layering of ILs. Extended layering was observed only when there is imidazolium ring in the cation. When the imidazolium ring is replaced by an aliphatic moiety, "drop-on-layer" (dewetting) structure was observed. On the basis of the experimental results, we proposed that π-π+ stacking between sp(2) carbon in the AC and the imidazolium cation in the ILs is the key to the extended layering of ILs at the ILs/AC interface.
authors: Xiao
authors: X
authors: Gong
authors: Andrew
authors: A
authors: Kozbial
authors: ‡San Jose Research Center, HGST, A Western Digital Company, 3403 Yerba Buena Road, San Jose, California 95135, United States.
authors: Franck
authors: F
authors: Rose
authors: Lei
authors: L
authors: Li
keywords: amorphous carbon; hard disk drives; ionic liquid; layering; media lubricant; π−π+ stacking