Lubricated friction and volume dilatancy are coupled
Lubricated friction and volume dilatancy are coupled
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润滑摩擦和体积膨胀耦合
DOI：
10.1063/1.1499476
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发表时间：
2002
影响因子：
4.4
通讯作者：
S. Granick
中科院分区：
文献类型：
--
作者：
A. L. Demirel;S. Granick
当受限膜从静止状态(“静态摩擦”)过渡到滑动(“动摩擦”)时，观察到∼0.1A的膨胀(膜厚膨胀)，小于受限流体分子宽度的十分之一。这些测量是基于使用具有极高分辨率的压电双晶片传感器来检测位置变化的，在角鲨烷分子薄膜的滑动过程中，角鲨烷是一种模型润滑剂，在原子上光滑的云母单晶之间滑动。能量平衡的详细检验表明，膨胀数据和摩擦力满足滑移点从静摩擦到动摩擦的可识别能量守恒。据我们所知，这第一次从实验上证明了摩擦力和介于其间的分子稀薄流体的平均密度降低之间的直接耦合。
Dilation (expansion of film thickness) by ∼0.1 A, which is less than one-tenth of the width of confined fluid molecules, was observed when confined films crossed from the resting state (“static friction”) to sliding (“kinetic friction”). These measurements were based on using piezoelectric bimorph sensors possessing extremely high resolution for detecting position changes, during the course of sliding molecularly thin films of squalane, a model lubricant fluid, between atomically smooth single crystals of mica. Detailed inspection of energy balance shows that the dilation data and the friction forces satisfied energy conservation of identifiable energies at the slip point, from static to kinetic friction. This shows experimentally, for the first time to the best of our knowledge, a direct coupling between friction forces and decrease in the mean density of the intervening molecularly thin fluid.