论文标题

驱动聚电解质溶液中的宏观电荷分离

Macroscopic charge segregation in driven polyelectrolyte solutions

论文作者

Bagchi, Debarshee

论文摘要

了解带电的复合液的行为对于大量重要的工业,技术和医学应用至关重要。使用粗粒分子动力学模拟,我们在这里研究了由稳定的电场驱动的,具有显式柜台和隐式溶剂的聚电解质溶液的性能。通过正确调整颗粒间静电和施加的电场之间的相互作用,我们发现了两个非平衡连续相变为驾驶场的函数。第一个过渡是从均质混合相到宏观电荷隔离相的,其中聚电解质溶液会自组织形成两个类似电荷的车道,并平行于所施加的场。我们表明,在电场的存在下,负责该电荷隔离的基本基本因素是漂流聚电解质链的排除体积相互作用。随着驱动的进一步增加,观察到从电荷分离相到均匀相的重点转变。随着电场的增加,单体和对抗的迁移率的降低表明了重新进入。此外,在多价柜台的情况下,观察到负差异迁移率的违反直觉状态,其中电荷随着驾驶场的增加而逐渐变慢。我们表明,所有这些功能都可以通过直观的陷阱机制来始终如一地解释,该机制在相对移动的指控之间运行,并提供数值证据来支持我们的主张。研究了参数依赖性和相图,以更好地理解这种驱动的聚电解质溶液中的电荷分离。

Understanding the behavior of charged complex fluids is crucial for a plethora of important industrial, technological, and medical applications. Using coarse-grained molecular dynamics simulations, here we investigate the properties of a polyelectrolyte solution, with explicit counterions and implicit solvent, that is driven by a steady electric field. By properly tuning the interplay between interparticle electrostatics and the applied electric field, we uncover two nonequilibrium continuous phase transitions as a function of the driving field. The first transition occurs from a homogeneously mixed phase to a macroscopically charge segregated phase, in which the polyelectrolyte solution self-organizes to form two lanes of like-charges, parallel to the applied field. We show that the fundamental underlying factor responsible for the emergence of this charge segregation in the presence of electric field is the excluded volume interactions of the drifting polyelectrolyte chains. As the drive is increased further, a re-entrant transition is observed from a charge segregated phase to a homogeneous phase. The re-entrance is signaled by the decrease in mobility of the monomers and counterions, as the electric field is increased. Furthermore, with multivalent counterions, a counterintuitive regime of negative differential mobility is observed, in which the charges move progressively slower as the driving field is increased. We show that all these features can be consistently explained by an intuitive trapping mechanism that operates between the oppositely moving charges, and present numerical evidence to support our claims. Parameter dependencies and phase diagrams are studied to better understand charge segregation in such driven polyelectrolyte solutions.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源