Electrokinetic flow of an aqueous electrolyte in amorphous silica nanotubes

Daub, Christopher D.; Cann, N. M.; Bratko, D.; Luzar, Alenka

doi:10.1039/c8cp03791d

Cited by 18 publications

(27 citation statements)

References 64 publications

(93 reference statements)

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“…However, recent studies showed that the consideration of polarizability can have a strong influence on the outcome of simulations of mineral-water interfaces, especially in the presence of large ions. [41][42][43][44][45][46] The consideration of polarizability at montmorillonite surface/water interfaces improved also significantly the quantitative agreement of MD predictions of interlayer space structure with XRD experimental results. [47][48][49][50][51] However, this improvement was obtained at a significant numerical cost, and the necessity to include polarizability in clay/water MD simulations must be then evaluated as a function of the system properties of interest.…”

Section: Introductionmentioning

confidence: 69%

Influence of Polarizability on the Prediction of the Electrical Double Layer Structure in a Clay Mesopore: A Molecular Dynamics Study

et al. 2020

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The prediction of the water and ion density profiles in the electrical double layer (EDL) is a key insight for macroscopic models that intend to model transport and swelling properties in clay materials. Unfortunately, the structure of the EDL, and especially the ion distribution, cannot be probed directly by measurements, because EDL features are inherently disturbed by direct measurement techniques. In recent years, Molecular Dynamics have provided a growing set of information on the properties of the EDL, including the properties of the diffuse layer, located beyond the Stern or compact layer, and in which a diffuse cloud of ions screens the remaining uncompensated surface charge. Molecular Dynamics results are, however, dependent on the force field used to run the simulations. In this study, we investigated the influence of the choice of a force field on the structural and dynamic properties of the EDL present at montmorillonite surface/water interfaces in a 50Å wide slit-shaped mesopore. Simulations were run in the presence and in the absence of added NaCl, and the results were compared to ion distributions in the diffuse layer predicted with a Poisson-Boltzmann model. The simulations evidenced the strong influence of the consideration of polarizability of ions and water molecules on the predicted structural and dynamic properties of the EDL. While non polarizable force fields gave results in good agreement with the prediction of the Poisson-Boltzmann theory, our tested polarizable force field, PIM, showed very significant deviations, which could be mainly attributed to the enhanced formation of ion pairs.

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Section: Introductionmentioning

confidence: 69%

Influence of Polarizability on the Prediction of the Electrical Double Layer Structure in a Clay Mesopore: A Molecular Dynamics Study

et al. 2020

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“…2(e) for NaCl aqueous solutions) indicates that the water molecules reorient when they come in contact with silica, with the hydrogen atoms approaching the surface closer than the oxygen. 16,26,27,33 The roughness of the silica surface facilitates the percolation of water through the solid. This is reflected in the slow decay of the water density profile as it meets the silica surface (see Fig.…”

Section: Resultsmentioning

confidence: 99%

Taming the thermodiffusion of alkali halide solutions in silica nanopores

2020

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“… 35 The effect of polarizable water models within synthetic nanoconfined environments under an electric field has also been investigated, with the conclusion that polarizability can affect the structure and dynamics of the systems. 36 – 38 Various rigid fixed-charge water models have also been assessed for ligand binding in host/guest systems 39 and for water behaviour in peptide nanotubes. 29 …”

Section: Introductionmentioning

confidence: 99%

Water Nanoconfined in a Hydrophobic Pore: Molecular Dynamics Simulations of Transmembrane Protein 175 and the Influence of Water Models

et al. 2021

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Water molecules within biological ion channels are in a nano-confined environment and therefore exhibit behaviours which differ from that of bulk water. Here, we investigate the phenomenon of hydrophobic gating, the process by which a nanopore may spontaneously de-wet to form a ‘vapour lock’ if the pore is sufficiently hydrophobic and/or narrow. This occurs without steric occlusion of the pore. Using molecular dynamics simulations with both rigid fixed-charge and polarizable (AMOEBA) force fields, we investigate this wetting/de-wetting behaviour in the TMEM175 ion channel. We examine how a range of rigid fixed-charge and polarizable water models affect wetting/de-wetting in both the wild-type structure and in mutants chosen to cover a range of nanopore radii and pore-lining hydrophobicities. Crucially, we find that the rigid fixed-charge water models lead to similar wetting/de-wetting behaviours, but that the polarizable water model resulted in an increased wettability of the hydrophobic gating region of the pore. This has significant implications for molecular simulations of nano-confined water, as it implies that polarizability may need to be included if we are to gain detailed mechanistic insights into wetting/de-wetting processes. These findings are of importance for the design of functionalised biomimetic nanopores (for e . g . sensing or desalination), as well as for furthering our understanding of the mechanistic processes underlying biological ion channel function.

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Electrokinetic flow of an aqueous electrolyte in amorphous silica nanotubes

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.

Cited by 18 publications

References 64 publications

Influence of Polarizability on the Prediction of the Electrical Double Layer Structure in a Clay Mesopore: A Molecular Dynamics Study

Influence of Polarizability on the Prediction of the Electrical Double Layer Structure in a Clay Mesopore: A Molecular Dynamics Study

Taming the thermodiffusion of alkali halide solutions in silica nanopores

Water Nanoconfined in a Hydrophobic Pore: Molecular Dynamics Simulations of Transmembrane Protein 175 and the Influence of Water Models

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