Document Type

Article

Original Publication Date

2018

Journal/Book/Conference Title

Physical Chemistry Chemical Physics

Volume

20

First Page

27838

Last Page

27848

DOI of Original Publication

10.1039/c8cp03791d

Comments

This article is the postprint version of the article published in October 2018 at https://doi.org/10.1039/c8cp03791d.

Date of Submission

October 2019

Abstract

We study the pressure-driven flow of aqueous NaCl in amorphous silica nanotubes using nonequilibrium molecular dynamics simulations featuring both polarizable and non-polarizable molecular models. Different pressures, electrolyte concentrations and pore sizes are examined. Our results indicate a flow that deviates considerably from the predictions of Poiseuille fluid mechanics. Due to preferential adsorption of the different ionic species by surface SiO! or SiOH groups, we find that a significant electric current is generated, but with opposite polarities using polarizable vs. fixed charge models for water and ions, emphasizing the need for careful parameterization in such complex systems. We also examine the influence of partial deprotonation of the silica surface, and we find that much more current is generated in a dehydrogenated nanopore, even though the overall efficiency remains low. These findings indicate that different methods of nanopore preparation, which can produce a range of surface properties, should be examined more closely in the related experimental methods to generate electrokinetic current.

Rights

© the Owner Societies 2018

Is Part Of

VCU Chemistry Publications

Included in

Chemistry Commons

Share

COinS