Consistent accounting of steric effects for prediction of streaming potential in narrow confinements
Consistent accounting of steric effects for prediction of streaming potential in narrow confinements
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DOI：
10.1103/physreve.86.061504
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发表时间：
2012-12-17
影响因子：
2.4
通讯作者：
Chakraborty, Suman
中科院分区：
文献类型：
--
作者：
Chakraborty, Jeevanjyoti;Dey, Ranabir;Chakraborty, Suman
用于确定流动电位的传统建模框架在考虑有限尺寸效应时受到忽略，因为虽然模型在离子分布曲线中结合了尺寸效应，但它忽略了通量贡献中的这些非常相同的效应，即使扩散率与离子摩擦内在地联系在一起，这又取决于离子的尺寸。这种疏忽可能会导致不一致的定量估计，通过特别考虑扩散率值，显然独立于离子的具体大小，但决定了离子的配置文件。我们补救这种理论上的不一致表示的扩散率的离子半径和调查的后果，这样一个描述的扩散率依赖的通量，与离子分布的配置文件，对流动电位介导的流量预测。此外，我们认为“电荷诱导增稠”的影响，使粘度和扩散率表示为空间变化的功能。作为一个不直观的含义，我们还表明，计算的非零值的经典玻尔兹曼分布，认为离子是点状电荷的范围内的流动电位，本身就是一个理论上的不一致。我们相信，本文中提出的简单框架将为未来更复杂的建模工作铺平道路。DOI：10.1103/PhysRevE.86.061504
The traditional modeling framework for determining streaming potential, when taking into consideration finite size effects, suffers from an oversight in that while the model incorporates the size effects in the ion distribution profiles, it neglects these very same effects in the flux contributions, even though diffusivities are intrinsically linked with ionic friction, which again depends on the size of the ions. This oversight may lead to inconsistent quantitative estimates through ad hoc consideration of diffusivity values, apparently independent of the specific size of the ions, which nevertheless determines the ionic profiles. We remedy this theoretical inconsistency by expressing the diffusivity in terms of the ionic radius and investigate the consequences of such a description of the diffusivity-dependent flux, consistent with the ionic distribution profiles, on streaming potential mediated flow predictions. Additionally, we consider the effects of "charge induced thickening" so that both viscosity and diffusivity are expressed as spatially varying functions. As an unintuitive implication, we also show that calculation of nonzero values of streaming potential under the purview of classical Boltzmann distributions, which consider ions to be pointlike charges, is itself a theoretical inconsistency. We believe that the simple framework presented in this paper will pave the way for more sophisticated modeling efforts in the future. DOI: 10.1103/PhysRevE.86.061504