Monte Carlo, density functional theory, and Poisson–Boltzmann theory study of the structure of an electrolyte near an electrode

Boda, Dezső; Fawcett, W. Ronald; Henderson, Douglas; Sokołowski, S.

doi:10.1063/1.1464826

Cited by 147 publications

(171 citation statements)

References 25 publications

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“…In Figure 3 we compare the ion distributions, g(x) = c(x)/c ∞ , predicted by the continuum model to those predicted by Monte Carlo simulations of Boda et al [53]. The conditions here are a 2:1 electrolyte with surface charge of -0.3 C/m 2 and an ion diameter of 0.3 nm.…”

Section: Validation a Comparison With Molecular Simulationsmentioning

confidence: 95%

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Effects of electrostatic correlations on electrokinetic phenomena

2012

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The classical theory of electrokinetic phenomena is based on the mean-field approximation, that the electric field acting on an individual ion is self-consistently determined by the local mean charge density. This paper considers situations, such as concentrated electrolytes, multivalent electrolytes, or solvent-free ionic liquids, where the mean-field approximation breaks down. A fourth-order modified Poisson equation is developed that captures the essential features in a simple continuum framework. The model is derived as a gradient approximation for non-local electrostatics of interacting effective charges, where the permittivity becomes a differential operator, scaled by a correlation length. The theory is able to capture subtle aspects of molecular simulations and allows for simple calculations of electrokinetic flows in correlated ionic fluids, for the first time. Charge-density oscillations tend to reduce electro-osmotic flow and streaming current, and over-screening of surface charge can lead to flow reversal. These effects also help to explain the suppression of induced-charge electrokinetic phenomena at high salt concentations.

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Section: Validation a Comparison With Molecular Simulationsmentioning

confidence: 95%

“…What is interesting about the continuum model with correlations included is that there are no fit parameters. [53] (points) and the continuum model with only steric effects (dashed lines). The ion diameter is 0.3 nm.…”

Section: Validation a Comparison With Molecular Simulationsmentioning

confidence: 99%

Effects of electrostatic correlations on electrokinetic phenomena

2012

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“…At any rate, the surface heterogeneity can have considerable effects on electrokinetic properties or colloidal forces. 16,17 Computer simulations have contributed to a better understanding of EDLs including multivalent ions and related phenomena challenging the classical theory, [18][19][20][21][22][23][24][25] such as charge inversion and attractive electrostatic forces between likecharge particles. [26][27][28][29] Computational methods can also become a valuable tool to shed light on surface heterogeneity effects.…”

Section: Introductionmentioning

confidence: 99%

Effect of the surface charge discretization on electric double layers: A Monte Carlo simulation study

Madurga

Vilaseca

Mas

et al. 2007

The Journal of Chemical Physics

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The structure of the electric double layer in contact with discrete and continuously charged planar surfaces is studied within the framework of the primitive model through Monte Carlo simulations. Three different discretization models are considered together with the case of uniform distribution. The effect of discreteness is analyzed in terms of charge density profiles. For point surface groups, a complete equivalence with the situation of uniformly distributed charge is found if profiles are exclusively analyzed as a function of the distance to the charged surface. However, some differences are observed moving parallel to the surface. Significant discrepancies with approaches that do not account for discreteness are reported if charge sites of finite size placed on the surface are considered.

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“…A modified version of the charged sheet method of Boda and co-workers 15,42,43 was implemented to correct the effects of truncating long-range interactions. For every ion in the solution, this method defines a sheet of infinite dimensions outside the simulation box, parallel to the charged wall and with the same charge as the ion.…”

Section: Model and Simulation Proceduresmentioning

confidence: 99%

A semi-grand canonical Monte Carlo simulation model for ion binding to ionizable surfaces: Proton binding of carboxylated latex particles as a case study

Madurga

Rey-Castro²,

Pastor³

et al. 2011

The Journal of Chemical Physics

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In this paper, we present a computer simulation study of the ion binding process at an ionizable surface using a semi-grand canonical Monte Carlo method that models the surface as a discrete distribution of charged and neutral functional groups in equilibrium with explicit ions modelled in the context of the primitive model. The parameters of the simulation model were tuned and checked by comparison with experimental titrations of carboxylated latex particles in the presence of different ionic strengths of monovalent ions. The titration of these particles was analysed by calculating the degree of dissociation of the latex functional groups vs. pH curves at different background salt concentrations. As the charge of the titrated surface changes during the simulation, a procedure to keep the electroneutrality of the system is required. Here, two approaches are used with the choice depending on the ion selected to maintain electroneutrality: counterion or coion procedures. We compare and discuss the difference between the procedures. The simulations also provided a microscopic description of the electrostatic double layer (EDL) structure as a function of pH and ionic strength. The results allow us to quantify the effect of the size of the background salt ions and of the surface functional groups on the degree of dissociation. The non-homogeneous structure of the EDL was revealed by plotting the counterion density profiles around charged and neutral surface functional groups.

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Monte Carlo, density functional theory, and Poisson–Boltzmann theory study of the structure of an electrolyte near an electrode

Cited by 147 publications

References 25 publications

Effects of electrostatic correlations on electrokinetic phenomena

Effects of electrostatic correlations on electrokinetic phenomena

Effect of the surface charge discretization on electric double layers: A Monte Carlo simulation study

A semi-grand canonical Monte Carlo simulation model for ion binding to ionizable surfaces: Proton binding of carboxylated latex particles as a case study

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