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arXiv · 1607.06838

Transport-induced inversion of screening ionic charges in nanochannels

Xin Zhu·Lingzi Guo·Sheng Ni·Xingye Zhang·Yang Liu
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Abstract

This work reveals a counter-intuitive but basic process of ionic screening in nano-fluidic channels. Steady-state numerical simulations and mathematical analysis show that, under significant longitudinal ionic transport, the screening ionic charges can be locally inverted in the channels: their charge sign becomes the same as that of the channel surface charges. The process is identified to originate from the coupling of ionic electro-diffusion transport and junction 2-D electrostatics. This finding may expand our understanding on ionic screening and electrical double layers in nano-channels. Furthermore, the charge inversion process results in a body-force torque on channel fluids, which is a possible mechanism for vortex generation in the channels and their nonlinear current-voltage characteristics.

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Xin Zhu, Lingzi Guo, Sheng Ni, Xingye Zhang, Yang Liu. 2016-07-22. Transport-induced inversion of screening ionic charges in nanochannels. https://doi.org/10.1021/acs.jpclett.6b02563

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