Frictional forces in polyelectrolyte brushes: effects of sliding velocity, solvent quality and salt
Frictional forces in polyelectrolyte brushes: effects of sliding velocity, solvent quality and salt
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DOI：
10.1039/c2sm07450h
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发表时间：
2012-01-01
期刊：
影响因子：
3.4
通讯作者：
Tildesley, Dominic J.
中科院分区：
文献类型：
--
作者：
Goujon, Florent;Ghoufi, Aziz;Tildesley, Dominic J.
用耗散粒子动力学(DPD)方法模拟了接枝聚合物刷在三种分离距离下的剪切行为。我们研究了剪切对中性和带电聚合物链形成的单分子膜和压缩双分子膜的影响。研究了两种压缩聚合物刷中不同电荷分数下的摩擦力与溶剂质量的关系。根据互穿系数的变化，分析了加盐后摩擦力的变化。我们通过对刷子结构的描述来完成这项研究，包括在不同的分离距离、盐浓度、电荷分数和剪切速率下的有序性、组成、倾斜度和局部电子中性性。有趣的是，聚电解质刷的单体密度分布中的一些非均质性在剪切下出现，并随着盐的加入而消失。
We report dissipative particle dynamics (DPD) simulations of grafted polymer brushes under shear at three separation distances. We investigate the impact of the shear on single monolayers and compressed bilayers formed by neutral and charged polymer chains. The dependence of the friction on the solvent quality is studied for different charge fractions in two compressed polymer brushes. The change in the frictional forces upon the addition of the salt is analyzed in terms of change in the interpenetration coefficient. We complete this study by a description of the brush structure including ordering, composition, tilt and local electroneutrality at different separation distances, salt concentrations, charge fractions and shear rates. Interestingly, some heterogeneities in the monomer density profiles of polyelectrolyte brushes appear under shear and vanish upon addition of salt.