arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1905.04053cond-mat.soft
收藏

多价阳离子介导的类电荷polymer -膜络合:单环修饰强耦合理论

Like-charge polymer-membrane complexation mediated by multivalent cations: one-loop-dressed strong coupling theory

Sahin Buyukdagli, Rudolf Podgornik

摘要:

我们探测静电机制驱动的聚电解质吸附到带相同电荷的膜后,加入三价和四价的抗衡离子的洗澡单价盐溶液。我们发展了一个单圈强耦合理论,将一价盐在静电单圈水平和多价抗衡离子在一个强耦合的方法。结果表明,介导同电荷吸附的多价反离子的粘附力来自它们在带电膜上的强烈凝聚。由此产生的界面抗衡过剩局部地最大化电解质的屏蔽能力,并最小化静电聚合物巨势。这转化为吸引力,将聚合物拉向类似电荷的膜。我们表明,高的反价,使这种吸附过渡,即使在弱电荷的膜。此外,强带电的膜引起盐诱导的相关性,并加强界面多价反离子缩合,加强聚合物与带相同电荷的膜的络合作用,以及触发分子的取向转变之前,其吸附。最后,我们的理论提供了两个额外的关键功能,如以前的吸附实验所证明的:第一,聚合物吸附的临界counterweight浓度随counterweight价的上升而下降,第二,单价盐的加入增强了膜电荷的筛选,抑制了盐的相关性。这削弱了界面多价反离子的凝聚,并导致聚合物从基底上脱附。

英文摘要:

We probe the electrostatic mechanism driving adsorption of polyelectrolytes onto like-charged membranes upon the addition of tri- and tetravalent counterions to a bathing monovalent salt solution. We develop a one-loop-dressed strong coupling theory that treats the monovalent salt at the electrostatic one-loop level and the multivalent counterions within a strong-coupling approach. It is shown that the adhesive force of the multivalent counterions mediating the like-charge adsorption arises from their strong condensation at the charged membrane. The resulting interfacial counterion excess locally maximizes the screening ability of the electrolyte and minimizes the electrostatic polymer grand potential. This translates into an attractive force that pulls the polymer to the similarly charged membrane. We show that the high counterion valency enables this adsorption transition even at weakly charged membranes. Additionally, strongly charged membranes give rise to salt-induced correlations and intensify the interfacial multivalent counterion condensation, strenghtening the complexation of the polymer with the like-charged membrane, as well as triggering the orientational transition of the molecule prior to its adsorption. Finally, our theory provides two additional key features as evidenced by previous adsorption experiments: first, the critical counterion concentration for polymer adsorption decreases with the rise of the counterion valency, and second, the addition of monovalent salt enhances the screening of the membrane charges and suppresses salt correlations. This weakens the interfacial multivalent counterion condensation and results in the desorption of the polymer from the substrate.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑