Density functional study on the osmotic coefficient for the DNA–electrolyte solutions

Yu, Yang−Xin; Wang, K e; Gao, Guang‐Hua

doi:10.1016/j.fluid.2006.09.029

Cited by 3 publications

(4 citation statements)

References 22 publications

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“…The Poisson–Boltzmann framework is employed throughout this article although the cell approximation can be invoked with more general theories not restricted to the weak coupling limit. Other classical cell models are the modified Poisson–Boltzmann (MPB) cell model, the DFT cell model, , and the HNC/MSA cell model . Since the results reported here were obtained in the Poisson–Boltzmann framework, they are strictly speaking relevant only in the weak coupling limit.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Assessment of the Accuracy of the Poisson–Boltzmann Cell Model for Salty Suspensions

2014

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The cell model is a ubiquitous, fast, and relatively easily implemented model used to estimate the osmotic pressure of a colloidal dispersion. It has been shown to yield accurate approximations of the pressure in dispersions with a low salt content. It is generally accepted that it performs well when long-ranged interactions are involved and the structure of the dispersion is solidlike. The aim of the present work is to determine quantitatively the error committed by assuming the pressure computed with the cell model is the real osmotic pressure of a dispersion. To this end, cell model pressures are compared to a correct estimation of the actual pressures obtained from Poisson-Boltzmann Brownian dynamics simulations including many-body electrostatics and the thermal motion of the colloids. The comparison is performed for various colloidal sizes and charges, salt contents, and volume fractions. It is demonstrated that the accuracy of the cell model predictions is a function of only the average intercolloid distance scaled by Debye's length κd̅ and the normalized colloidal charge. The cell model is accurate for κd̅ < 1 and not reliable for κd̅ > 5 independently of the colloidal charge. In the 1 < κd̅ < 5 range, covering a wide set of experimental conditions, the colloidal surface charge has a large influence on the error associated with the cell approximation. The results presented in this article should provide a useful reference to determine a priori if the cell model can be expected to predict accurately an equation of state for a given set of physicochemical parameters.

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Section: Introductionmentioning

confidence: 99%

Quantitative Assessment of the Accuracy of the Poisson–Boltzmann Cell Model for Salty Suspensions

2014

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“…5 Although the complicated models give some accurate descriptions of the structure of DNA, 6 the simple charged cylinder model combined with the primitive model of electrolyte solution can catch some basic characteristic properties of the EDL around DNA and is capable of reproducing with experiments at most conditions. 7,8 The theoretical studies of physical properties of aqueous DNA solution started from the famous counterion condensa-tion ͑CC͒ theory established by Manning. 9 This theory has been successfully applied in the calculation of the limiting behavior of thermodynamic properties 10,11 and now is extended to take account of both finite counterion concentration and actual structure of the array of discrete charges by Schurr and Fujimoto 12 with an alternative auxiliary assumption.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a DFT, 22,26 which is a combination of a modified fundamental measure theory ͑MFMT͒ proposed by Yu and Wu, 27 with the electrical interaction term obtained by using a quadratic Taylor expansion with respect to a uniform fluid, 25,26 has proved to be more accurate than the PB and HNC/MSA theories. This scheme has been used in our previous works 7,8,22,28 to study the structural and thermodynamic properties for the infinitely dilute DNA solutions.…”

Section: Introductionmentioning

confidence: 99%

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Density functional study on the structural and thermodynamic properties of aqueous DNA-electrolyte solution in the framework of cell model

Wang

Gao

2008

The Journal of Chemical Physics

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A density functional theory (DFT) in the framework of cell model is proposed to calculate the structural and thermodynamic properties of aqueous DNA-electrolyte solution with finite DNA concentrations. The hard-sphere contribution to the excess Helmholtz energy functional is derived from the modified fundamental measure theory, and the electrostatic interaction is evaluated through a quadratic functional Taylor expansion around a uniform fluid. The electroneutrality in the cell leads to a variational equation with a constraint. Since the reference fluid is selected to be a bulk phase, the Lagrange multiplier proves to be the potential drop across the cell boundary (Donnan potential). The ion profiles and electrostatic potential profiles in the cell are calculated from the present DFT-cell model. Our DFT-cell model gives better prediction of ion profiles than the Poisson-Boltzmann (PB)- or modified PB-cell models when compared to the molecular simulation data. The effects of polyelectrolyte concentration, ion size, and added-salt concentration on the electrostatic potential difference between the DNA surface and the cell boundary are investigated. The expression of osmotic coefficient is derived from the general formula of grand potential. The osmotic coefficients predicted by the DFT are lower than the PB results and are closer to the simulation results and experimental data.

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Comparison of zeta potentials and structure for statistical mechanical theories of a model cylindrical double layer

González‐Tovar

Lozada‐Cassou

Bhuiyan

et al. 2018

Journal of Molecular Liquids

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Density functional study on the osmotic coefficient for the DNA–electrolyte solutions

Cited by 3 publications

References 22 publications

Quantitative Assessment of the Accuracy of the Poisson–Boltzmann Cell Model for Salty Suspensions

Quantitative Assessment of the Accuracy of the Poisson–Boltzmann Cell Model for Salty Suspensions

Density functional study on the structural and thermodynamic properties of aqueous DNA-electrolyte solution in the framework of cell model

Comparison of zeta potentials and structure for statistical mechanical theories of a model cylindrical double layer

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