Polyelectrolytes in electric fields: measuring the dynamical effective charge and effective friction
Polyelectrolytes in electric fields: measuring the dynamical effective charge and effective friction
复制标题
电场中的聚电解质：测量动态有效电荷和有效摩擦
DOI：
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Christian Holm
中科院分区：
文献类型：
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作者：
K. Grass;Christian Holm
我们使用粗粒度分子动力学模型来研究柔性聚电解质链的电泳行为。我们首先描述了模型在链长、聚电解质浓度、附加盐和所施加的外部场的影响方面的静态特性。接下来，我们研究低聚物范围内的动态行为，并在模拟中考虑流体动力学相互作用时发现模拟与实验观察的良好对应关系。然后，我们提出了自由溶液电泳期间动态有效电荷的新颖估计器，并将它们与静态估计器进行比较。我们发现静态估计器和动态估计器之间完全一致。我们进一步评估了聚电解质-抗衡离子复合物与周围流体的有效摩擦的结垢行为。我们确定了一个流体动力学筛选长度，超过该长度，电泳期间的摩擦力根据链长度呈线性，从而导致长聚电解质链具有恒定的迁移率。我们的结果与实验数据令人信服地一致，并证明可以使用粗粒度模型对聚电解质的动态行为进行建模，只要它们包括流体动力学相互作用的影响。
We use a coarse-grained molecular dynamics model to study the electrophoretic behaviour of flexible polyelectrolyte chains. We first characterize the static properties of the model with respect to the chain length, the polyelectrolyte concentration, additional salt and the influence of an applied external field. Next we investigate the dynamic behaviour in the oligomer range and find excellent correspondence of simulations to experimental observations when hydrodynamic interactions are accounted for in the simulations. We then present novel estimators for the dynamical effective charge during free-solution electrophoresis and compare them to static estimators. We find complete agreement between the static and the dynamic estimators. We further evaluate the scaling behaviour of the effective friction of the polyelectrolyte-counterion complex with the surrounding fluid. We identify a hydrodynamic screening length beyond which the friction during electrophoresis is linear depending on the chain length resulting in a constant mobility for long polyelectrolyte chains. Our results show a convincing agreement with experimental data and demonstrate that it is possible to model dynamic behaviour of polyelectrolytes using coarse-grained models, provided they include the effects of hydrodynamical interactions.
DOI：
10.1080/07391102.1998.10508261
发表时间：
1998-10-01
影响因子：
4.4
作者：
Manning, GS;Ray, J
通讯作者：
Ray, J