Micro/macrotribological properties of several nano-scale ionic liquid films on modified silicon wafers

Three kinds of alkylimidazolium base room temperature ionic liquids (RTILs) were synthesized and their nano-scale lubricant films were prepared on modified silicon wafers by dip-coating method. The thicknesses of these films were measured and their relationship between thickness and solution concentration was obtained. Their surface morphologies were observed and contact angles of water on these films were determined. The adhesions and friction coefficients of these films were detected by contact mode AFM. As comparison, their macrotribological properties were evaluated on a UMT-2MT tribo-tester. It was found that, in microscale, 1-hexyl-3-methyl-imidazolium hexafluorophosphate performed the best tribological properties, while in macroscale, its tribological properties were similar with that of 1-hexyl-3-methyl-imidazolium tetrafluoroborate and better than that of 1-hexyl-3-methyl-imidazolium adipate. Copyright (C) 2009 John Wiley & Sons, Ltd.