Molecular Layering in Nanometer-Confined Lubricants
Molecular Layering in Nanometer-Confined Lubricants
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纳米润滑剂中的分子分层
DOI：
10.1007/s11249-018-1041-y
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
R. Bennewitz
中科院分区：
文献类型：
--
作者：
Marc;G. Krämer;U. Dellwo;R. Bennewitz
利用原子力显微镜研究了聚α -烯烃（PAO）和酯类润滑油在纳米尺度约束下的分子分层现象。在石墨、云母和抛光钢表面上的聚（1-癸烯）四聚体（PAO6）和十一聚体（PAO40）以及2-乙基己基单酯的力-距离曲线中观察到分层，并将其与十六烷和1-十六烯的分层进行比较。在石墨表面，受限制的分子取向与所有液体的表面平行，从而形成厚度与烷基链直径相当的层。在云母上，受限的十六烷分子也平行于表面，而1-十六烯和PAOs的第一层分子则采取更直立的方向。在氧化抛光钢表面上的约束导致分子分层，这通常类似于石墨上的分层，与离子氧化云母上的分层有很大不同。
Molecular layering of liquids in nanometer-scale confinement is demonstrated for typical lubricant constituents such as polyalphaolefins (PAO) and an ester by means of atomic force microscopy. Layering is observed in force vs. distance curves for poly-(1-decene) tetramers (PAO6) and undecamers (PAO40) and for a 2-ethylhexyl monoester on graphite, mica, and polished steel surfaces and is compared to the layering of hexadecane and 1-hexadecene. On graphite surfaces, the confined molecules are oriented parallel to the surfaces for all liquids, resulting in layers with a thickness comparable to the diameter of the alkyl chains. On mica, confined hexadecane molecules also lie parallel to the surface, while the molecules in the first layer of 1-hexadecene and PAOs take a more upright orientation. Confinement on the oxidized polished steel surfaces results in a molecular layering which most often resembles the layering on graphite and differs significantly from layering on the ionic oxide mica.