Frictional Forces between Strongly Compressed, Nonentangled Polymer Brushes: Molecular Dynamics Simulations and Scaling Theory
Frictional Forces between Strongly Compressed, Nonentangled Polymer Brushes: Molecular Dynamics Simulations and Scaling Theory
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DOI：
10.1021/la904119c
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发表时间：
2010-05-04
期刊：
影响因子：
3.9
通讯作者：
Baschnagel, J.
中科院分区：
文献类型：
--
作者：
Galuschko, A.;Spirin, L.;Baschnagel, J.
通过分子动力学模拟和标度理论，我们研究了在良溶剂条件下，相对的聚合物刷对恒定剪切运动的响应。模型系统，包含明确的溶剂分子（Lennard-Jones二聚体）进行比较，无溶剂的系统，而不同的接枝层之间的距离和它们的分子参数，链长和接枝密度。我们的研究揭示了幂律依赖的宏观输运性质的Weissenberg数，W，超越线性响应。例如，我们发现，对于大的W值，动摩擦常数的标度为μ，类似于W-0.57。我们开发了一个标度理论，描述了我们的数据和以前的数值数据，包括最近的实验。
By means of molecular dynamics simulations and scaling theory we study the response or opposing polymer brushes to constant shear motion under good solvent conditions. Model systems that contain explicit solvent molecules (Lennard-Jones dimers) are compared to solvent-free systems while varying of the distance between the grafted layers and their molecular parameters, chain length and grafting density. Our study reveals a power-law dependence of macroscopic transport properties on the Weissenberg number, W, beyond linear response. For instance, we find that the kinetic friction constant scales as mu similar to W-0.57 for large values of W. We develop a scaling theory that describes our data and previous numerical data including recent experiments.