Paris-Saclay University, CNRS, Solid State Physics Laboratory, 91405 Orsay, France.
CEA Saclay, Léon Brillouin Laboratory, 91191 Gif-sur-Yvette, France.
Phys Rev E. 2023 Feb;107(2-2):025101. doi: 10.1103/PhysRevE.107.025101.
The effect of temperature on friction and slip at the liquid-solid interface has attracted attention over the last 20 years, both numerically and experimentally. However, the role of temperature on slip close to the glass transition has been less explored. Here we use molecular dynamics to simulate a bidisperse atomic fluid, which can remain liquid below its melting point (supercooled state), to study the effect of temperature on friction and slip length between the liquid and a smooth apolar wall in a broad range of temperatures. At high temperatures, an Arrhenius law fits well the temperature dependence of viscosity, friction, and slip length. In contrast, when the fluid is supercooled, the viscosity becomes super-Arrhenian, while interfacial friction can remain Arrhenian or even drastically decrease when lowering the temperature, resulting in a massive increase of the slip length. We rationalize the observed superlubricity by the surface crystallization of the fluid, and the incommensurability between the structures of the fluid interfacial layer and of the wall. This study calls for experimental investigation of the slip length of supercooled liquids on low surface energy solids.
过去 20 年来，人们在数值和实验上都对温度对固-液界面摩擦和滑移的影响产生了兴趣。然而，温度对接近玻璃化转变时滑移的作用研究得较少。在这里，我们使用分子动力学模拟了一种二组分原子流体，它可以在低于其熔点（过冷状态）的温度下保持液态，以研究温度对液体和光滑非极性壁之间的摩擦和滑移长度的影响。在高温下，阿累尼乌斯定律很好地拟合了粘度、摩擦和滑移长度随温度的变化关系。相比之下，当流体过冷时，粘度变得超阿累尼乌斯，而界面摩擦力可以保持阿累尼乌斯，甚至在降低温度时急剧下降，导致滑移长度大幅增加。我们通过流体的表面结晶和流体界面层与壁的结构之间的非一致性来解释观察到的超滑现象。这项研究呼吁对过冷液体在低表面能固体上的滑移长度进行实验研究。
