Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
Sci Rep. 2021 Jul 26;11(1):15216. doi: 10.1038/s41598-021-94477-x.
In this paper, we report for the first time overlimiting current near a nanochannel using all-atom molecular dynamics (MD) simulations. Here, the simulated system consists of a silicon nitride nanochannel integrated with two reservoirs. The reservoirs are filled with [Formula: see text] potassium chloride (KCl) solution. A total of [Formula: see text] million atoms are simulated with a total simulation time of [Formula: see text] over [Formula: see text] 30000 CPU hours using 128 core processors (Intel(R) E5-2670 2.6 GHz Processor). The origin of overlimiting current is found to be due to an increase in chloride ([Formula: see text]) ion concentration inside the nanochannel leading to an increase in ionic conductivity. Such effects are seen due to charge redistribution and focusing of the electric field near the interface of the nanochannel and source reservoir. Also, from the MD simulations, we observe that the earlier theoretical and experimental postulations of strong convective vortices resulting in overlimiting current are not the true origin for overlimiting current. Our study may open up new theories for the mechanism of overlimiting current near the nanochannel interconnect devices.
本文首次通过全原子分子动力学（MD）模拟报告了纳米通道中超限电流的现象。在这个模拟系统中，硅氮化物纳米通道与两个储层集成在一起。储层中充满了[Formula: see text]摩尔浓度的[Formula: see text]氯化钾（KCl）溶液。使用 128 核处理器（Intel(R) E5-2670 2.6GHz 处理器），总共模拟了[Formula: see text]万个原子，总模拟时间为[Formula: see text]，超过[Formula: see text]30000 CPU 小时。超限流的起源是由于纳米通道内氯离子([Formula: see text])浓度的增加，导致离子电导率的增加。这种效应是由于电荷重新分布和电场在纳米通道与源储层界面附近的聚焦而产生的。此外，通过 MD 模拟，我们观察到，先前关于强对流涡旋导致超限流的理论和实验假设并不是超限流的真正原因。我们的研究可能为纳米通道互连器件中超限流的机制提供新的理论依据。
