Linear response functions of an electrolyte solution in a uniform flow
Linear response functions of an electrolyte solution in a uniform flow
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DOI：
10.1103/physreve.98.032604
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发表时间：
2018-06
影响因子：
2.4
通讯作者：
Ram M. Adar;Y. Uematsu;S. Komura;D. Andelman
中科院分区：
文献类型：
--
作者：
Ram M. Adar;Y. Uematsu;S. Komura;D. Andelman
我们研究了相对于流体具有恒定相对速度的外源对单价稀电解质溶液的稳态响应。源被认为是三种扰动的组合：作用在流体上的外力、外部施加的离子化学势和外部电荷密度。线性响应函数是解析的，可以分解为三个独立的项，分别对应于(I)流体流量和压力，(Ii)总离子数密度和电流，(Iii)电荷密度，静电势和电流。结果表明，均匀流破坏了响应函数的平衡径向对称性，导致离子云和静电势的扭曲，这偏离了标准的德拜-H“uckel结果。运动电荷的势在其运动方向上被欠屏蔽，而在相反方向和法面上被过度屏蔽。结果是在远离带电源处感应出未屏蔽的偶极电场和电流。我们将我们的一般形式与几个实验装置联系起来，例如胶体沉积。
We study the steady state response of a dilute monovalent electrolyte solution to an external source with a constant relative velocity with respect to the fluid. The source is taken as a combination of three perturbations: an external force acting on the fluid, an externally imposed ionic chemical potential, and an external charge density. The linear response functions are obtained analytically and can be decoupled into three independent terms, corresponding to (i) fluid flow and pressure, (ii) total ionic number density and current, and (iii) charge density, electrostatic potential and electric current. It is shown how the uniform flow breaks the equilibrium radial symmetry of the response functions, leading to a distortion of the ionic cloud and electrostatic potential, which deviate from the standard Debye-H\"uckel result. The potential of a moving charge is under-screened in its direction of motion and over-screened in the opposite direction and normal plane. As a result, an unscreened dipolar electric field and electric currents are induced far from the charged source. We relate our general formalism to several experimental setups, such as colloidal sedimentation.