AFM-based nanotribological and electrical characterization of ultrathin wear-resistant ionic liquid films
AFM-based nanotribological and electrical characterization of ultrathin wear-resistant ionic liquid films
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DOI：
10.1016/j.jcis.2007.09.046
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发表时间：
2008-01-01
影响因子：
9.9
通讯作者：
Kinzig, Barbara
中科院分区：
文献类型：
--
作者：
Bhushan, Bharat;Palacio, Manuel;Kinzig, Barbara
离子液体(ILS)具有良好的导热性和导电性，被认为是微/纳米机电系统(MEMS/NEMS)的润滑剂。到目前为止，只对这些材料进行了宏观摩擦磨损试验。评估离子液体作为几纳米厚的薄膜应用于衬底时的纳米级摩擦学性能是了解这些新材料如何有效地润滑MEMS/NEMS器件的关键一步。为此，首次用原子力显微镜研究了离子液体1-丁基-3-甲基咪唑六氟磷酸盐(BMIM-PF6)和1-丁基-3-甲基咪唑辛基硫酸盐(BMIM-OctSO(4))在Si(100)表面上的粘着、摩擦和磨损性能。数据与全氟聚醚润滑剂Z-TETRAOL进行了比较，Z-TETRAOL具有高热稳定性和极低的蒸气压。利用基于AFM的表面电势和接触电阻技术，模拟了超低载荷下的磨损，研究了润滑剂的去除机理。与完全结合的涂层相比，含有流动润滑剂(即部分结合)的热处理涂层能够更好地保护硅衬底免受磨损，这种增强的保护归功于润滑剂的补充。(C)2007 Elsevier Inc.保留所有权利。
Ionic liquids (ILs) are considered as lubricants for micro/nanoelectromechanical systems (MEMS/NEMS) due to their excellent thermal and electrical conductivity. So far, only macroscale friction and wear tests have been conducted on these materials. Evaluating the nanoscale tribological performance of ILs when applied as a few nanometers-thick film on a substrate is a crucial step to understand how these novel materials can efficiently lubricate MEMS/NEMS devices. To this end, the adhesion, friction and wear properties of two ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) and 1-butyl-3-methylimidazolium octyl sulfate (BMIM-OctSO(4)), applied on Si(100), are investigated for the first time using atomic force microscopy (AFM). Data is compared to the perfluoropolyether lubricant Z-TETRAOL, which has high thermal stability and extremely low vapor pressure. Wear at ultralow loads was simulated and the lubricant removal mechanism was investigated using AFM-based surface potential and contact resistance techniques. Thermally treated coatings containing a mobile lubricant fraction (i.e., partially bonded) were better able to protect the Si substrate from wear compared to the fully bonded coatings, and this enhanced protection is attributed to lubricant replenishment. (c) 2007 Elsevier Inc. All rights reserved.