Ivaništšev V, Kirchner K, Kirchner T, Fedorov M V
Department of Physics, Scottish Universities Physics Alliance (SUPA), Strathclyde University, John Anderson Building, 107 Rottenrow East, Glasgow G4 0NG, UK. Institute of Chemistry, University of Tartu, Ravila 14A, 50114 Tartu, Estonia.
J Phys Condens Matter. 2015 Mar 18;27(10):102101. doi: 10.1088/0953-8984/27/10/102101. Epub 2015 Feb 13.
We have investigated the electrical double layer (EDL) structure at an interface between ionic liquid (IL) and charged surface using molecular dynamics simulations. We show that for three different models of ILs the EDL restructuring, driven by surface charging, can be rationalized by the use of two parameters--renormalized surface charge (κ) and charge excess in the interfacial layers (λ). Analysis of the relationship between the λ and κ parameters provides new insights into mechanisms of over-screening and charge-driven structural transitions in the EDL in ionic liquids. We show that the restructuring of the EDL upon charging in all three studied systems has two characteristic regimes: (1) transition from the bulk-like (κ(Ion) = 0) to the multilayer structure (κ(Ion) ≈ 0.5) through the formation of an ionic bilayer of counter- and co-ions; and (2) transition from the multilayer (κ(Ion) ≈ 0.5) to the crowded (κ(Ion) > 1) structure through the formation of a monolayer of counter-ions at κ(Ion) = 1.
我们利用分子动力学模拟研究了离子液体（IL）与带电表面之间界面处的双电层（EDL）结构。我们表明，对于三种不同的离子液体模型，由表面电荷驱动的EDL重组可以通过使用两个参数——重整化表面电荷（κ）和界面层中的电荷过量（λ）来合理化。对λ和κ参数之间关系的分析为离子液体中EDL的过屏蔽和电荷驱动结构转变机制提供了新的见解。我们表明，在所有三个研究系统中充电时EDL的重组有两个特征阶段：（1）通过形成抗衡离子和共离子的离子双层，从类本体（κ（离子） = 0）转变为多层结构（κ（离子）≈ 0.5）；（2）在κ（离子） = 1时通过形成单层抗衡离子，从多层（κ（离子）≈ 0.5）转变为拥挤结构（κ（离子）> 1）。
