Charged nanorods at heterogeneously charged surfaces.
Charged nanorods at heterogeneously charged surfaces.
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DOI：
10.1063/1.5044391
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
A. Naji;Kasra Hejazi;Elnaz Mahgerefteh;R. Podgornik
中科院分区：
文献类型：
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作者：
A. Naji;Kasra Hejazi;Elnaz Mahgerefteh;R. Podgornik
我们研究了带电纳米棒（棒状抗衡离子）的空间和取向分布以及它们在两个平面平行表面之间介导的有效相互作用，这些表面携带固定（淬灭）异质电荷分布。假设纳米棒具有由多价单极矩和有限四极矩指定的内部电荷分布，并且假设淬灭的表面电荷在两个表面上以相等的平均值和方差随机分布。虽然在传统的平均场理论中，相等电荷的表面被认为是排斥的，但多价抗衡离子的存在已被证明会导致均匀带电表面之间的吸引力相互作用，这是由于强静电耦合的普遍存在，这种耦合会随着反价迅速增长。我们表明，由于静电相关（由平均表面场和多价，单极，电荷价的反离子之间的耦合所造成的）以及无序诱导的相互作用（由表面无序场和反离子的四极矩之间的耦合所造成的）的综合效应导致更强的吸引力之间的相互作用两个随机带电的表面。的相互作用的配置文件原来是一个非单调函数的界面分离，显示在相对较小的分离，其中随后的吸引力可以超过最大的强耦合吸引力（由均匀带电的表面之间的多价单极抗衡离子）超过一个数量级的吸引力最小。
We study the spatial and orientational distribution of charged nanorods (rodlike counterions) as well as the effective interaction mediated by them between two plane-parallel surfaces that carry fixed (quenched) heterogeneous charge distributions. The nanorods are assumed to have an internal charge distribution, specified by a multivalent monopolar moment and a finite quadrupolar moment, and the quenched surface charge is assumed to be randomly distributed with equal mean and variance on the two surfaces. While equally charged surfaces are known to repel within the traditional mean-field theories, the presence of multivalent counterions has been shown to cause attractive interactions between uniformly charged surfaces due to the prevalence of strong electrostatic couplings that grow rapidly with the counterion valency. We show that the combined effects due to electrostatic correlations (caused by the coupling between the mean surface field and the multivalent, monopolar, charge valency of counterions) as well as the disorder-induced interactions (caused by the coupling between the surface disorder field and the quadrupolar moment of counterions) lead to much stronger attractive interactions between two randomly charged surfaces. The interaction profile turns out to be a nonmonotonic function of the intersurface separation, displaying an attractive minimum at relatively small separations, where the ensuing attraction can exceed the maximum strong-coupling attraction (produced by multivalent monopolar counterions between uniformly charged surfaces) by more than an order of magnitude.