Institut Charles Sadron, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France.
Langmuir. 2010 May 4;26(9):6418-29. doi: 10.1021/la904119c.
By means of molecular dynamics simulations and scaling theory we study the response of 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 approximately W(0.57) for large values of W. We develop a scaling theory that describes our data and previous numerical data including recent experiments.
我们通过分子动力学模拟和标度理论研究了在良溶剂条件下，恒定剪切运动对相互对抗的聚合物刷的响应。我们将包含显式溶剂分子（Lennard-Jones 二聚体）的模型系统与无溶剂系统进行了比较，同时改变了接枝层之间的距离及其分子参数、链长和接枝密度。我们的研究揭示了宏观输运性质对 Weissenberg 数 W 的幂律依赖性，超出了线性响应范围。例如，我们发现对于较大的 W 值，动力学摩擦常数的标度为 mu approximately W(0.57)。我们开发了一种标度理论来描述我们的数据和以前的数值数据，包括最近的实验。
