Chemical and physical origins of friction on surfaces with atomic steps
Chemical and physical origins of friction on surfaces with atomic steps
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DOI：
10.1126/sciadv.aaw0513
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发表时间：
2019-08-01
期刊：
影响因子：
13.6
通讯作者：
Kim, Seong H.
中科院分区：
文献类型：
--
作者：
Chen, Zhe;Khajeh, Arash;Kim, Seong H.
摩擦是通过一系列复杂的过程发生的，这些过程共同作用以抵抗相对运动。然而，尽管这种复杂性，摩擦通常使用简单的现象学表达式来描述，该表达式通过系数（摩擦系数）将法向力和侧向力关联起来。这一个参数包含多个，有时是竞争性的影响。为了更好地理解摩擦的起源，在这里，我们研究了二氧化硅和石墨之间具有单层石墨烯台阶边缘的化学和形貌上定义良好的界面。我们确定的物理和化学过程中的摩擦的单独贡献，并表明，一个单一的摩擦系数可以分为两项对应于这些效果。这些发现提供了深入了解摩擦的化学和地形起源，并建议通过利用竞争摩擦过程来调整表面的方法。
Friction occurs through a complex set of processes that act together to resist relative motion. However, despite this complexity, friction is typically described using a simple phenomenological expression that relates normal and lateral forces via a coefficient, the friction coefficient. This one parameter encompasses multiple, sometimes competing, effects. To better understand the origins of friction, here, we study a chemically and topographically well-defined interface between silica and graphite with a single-layer graphene step edge. We identify the separate contributions of physical and chemical processes to friction and show that a single friction coefficient can be separated into two terms corresponding to these effects. The findings provide insight into the chemical and topographic origins of friction and suggest means of tuning surfaces by leveraging competing frictional processes.