Mondal Debasish, Muthukumar M
Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA.
J Chem Phys. 2016 Aug 28;145(8):084906. doi: 10.1063/1.4961505.
We report a three dimensional Langevin dynamics simulation of a uniformly charged flexible polyelectrolyte chain, translocating through an asymmetric narrow channel with periodically varying cross sections under the influence of a periodic external electric field. When reflection symmetry of the channel is broken, a rectification effect is observed with a favored direction for the chain translocation. For a given volume of the channel unit and polymer length, the rectification occurs below a threshold frequency of the external periodic driving force. We have also observed that the extent of the rectification varies non-monotonically with increasing molecular weight and the strength of geometric asymmetry of the channel. Observed non-monotonicity of the rectification performance has been interpreted in terms of a competition between two effects arising from the channel asymmetry and change in conformational entropy. An analytical model is presented with predictions consistent with the simulation results.
我们报告了一个均匀带电的柔性聚电解质链的三维朗之万动力学模拟，该链在周期性外部电场的影响下，通过具有周期性变化横截面的不对称狭窄通道进行转运。当通道的反射对称性被打破时，观察到整流效应，链的转运具有一个有利的方向。对于给定的通道单元体积和聚合物长度，整流在外部周期性驱动力的阈值频率以下发生。我们还观察到，整流程度随分子量和通道几何不对称强度的增加而非单调变化。观察到的整流性能的非单调性已根据通道不对称和构象熵变化产生的两种效应之间的竞争来解释。提出了一个解析模型，其预测与模拟结果一致。
