A unifying mode-coupling theory for transport properties of electrolyte solutions. II. Results for equal-sized ions electrolytes

Contreras-Aburto, Claudio; Nägele, Gerhard

doi:10.1063/1.4822298

Cited by 24 publications

(7 citation statements)

References 76 publications

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“…Using the RP approximation in conjunction with the analytic PY solution for the Laplace transform of r g(r), Contreras-Aburto et al [78] have derived analytic expressions for the short-time sedimentation coefficient of Navier partial-slip and uniformly permeable spheres with hard-core interaction. Here, we present the according expression for spherical annulus particles, which includes hydrodynamic point particles as a limiting case for which K(φ, γ = 0) = 1.…”

Section: Sedimentation Coefficientmentioning

confidence: 99%

Dynamics of suspensions of hydrodynamically structured particles: analytic theory and applications to experiments

et al. 2015

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We present an easy-to-use analytic toolbox for the calculation of short-time transport properties of concentrated suspensions of spherical colloidal particles with internal hydrodynamic structure, and direct interactions described by a hard-core or soft Hertz pair potential. The considered dynamic properties include self-diffusion and sedimentation coefficients, the wavenumber-dependent diffusion function determined in dynamic scattering experiments, and the high-frequency shear viscosity. The toolbox is based on the hydrodynamic radius model (HRM) wherein the internal particle structure is mapped on a hydrodynamic radius parameter for unchanged direct interactions, and on an existing simulation data base for solvent-permeable and spherical annulus particles. Useful scaling relations for the diffusion function and self-diffusion coefficient, known to be valid for hard-core interaction, are shown to apply also for soft pair potentials. We further discuss extensions of the toolbox to long-time transport properties including the low-shear zero-frequency viscosity and the long-time self-diffusion coefficient. The versatility of the toolbox is demonstrated by the analysis of a previous light scattering study of suspensions of non-ionic PNiPAM microgels [Eckert et al., J. Chem. Phys., 2008, 129, 124902] in which a detailed theoretical analysis of the dynamic data was left as an open task. By the comparison with Hertz potential based calculations, we show that the experimental data are consistently and accurately described using the Verlet-Weis corrected Percus-Yevick structure factor as input, and for a solvent penetration length equal to three percent of the excluded volume radius. This small solvent permeability of the microgel particles has a significant dynamic effect at larger concentrations.

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Section: Sedimentation Coefficientmentioning

confidence: 99%

Dynamics of suspensions of hydrodynamically structured particles: analytic theory and applications to experiments

et al. 2015

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“…Our aim in implementing the SMCT is twofold: First, it serves as an independent dynamical theory to calculate the long-time self-diffusion coefficient (note, however, that the SMCT needs as input the static structure functions obtained from the simulations). Second, the SMCT has been used with success in the study of both self-and collective transport properties in homogeneous mixtures; 13 here, we show that the layered system constitutes another example in which the SMCT can be straightforwardly applied.…”

Section: Introductionmentioning

confidence: 77%

“…We are well aware of the fact that particle size effects play an important role in determining transport properties. 13 However, it is fair to say that the probability of contact is very small in systems of particles with equal charge sign that have K α values not too small and κ value not too large. In P1, we verified that the structure functions of Yukawa-like particles for various sets of parameters (n α , K α , κ), with hard-core corresponding to a particle diameter σ /d = 0.357 (calculated by means of Monte Carlo simulations and the hypernetted chain integral equation), and without hard-core (calculated by means of BD simulations), are in good agreement.…”

Section: Model Systems Notation and Simulation Detailsmentioning

confidence: 99%

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Long-time self-diffusion of charged spherical colloidal particles in parallel planar layers

Contreras-Aburto

Báez

Méndez‐Alcaraz

et al. 2014

The Journal of Chemical Physics

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The long-time self-diffusion coefficient, D(L), of charged spherical colloidal particles in parallel planar layers is studied by means of Brownian dynamics computer simulations and mode-coupling theory. All particles (regardless which layer they are located on) interact with each other via the screened Coulomb potential and there is no particle transfer between layers. As a result of the geometrical constraint on particle positions, the simulation results show that D(L) is strongly controlled by the separation between layers. On the basis of the so-called contraction of the description formalism [C. Contreras-Aburto, J. M. Méndez-Alcaraz, and R. Castañeda-Priego, J. Chem. Phys. 132, 174111 (2010)], the effective potential between particles in a layer (the so-called observed layer) is obtained from integrating out the degrees of freedom of particles in the remaining layers. We have shown in a previous work that the effective potential performs well in describing the static structure of the observed layer (loc. cit.). In this work, we find that the D(L) values determined from the simulations of the observed layer, where the particles interact via the effective potential, do not agree with the exact values of D(L). Our findings confirm that even when an effective potential can perform well in describing the static properties, there is no guarantee that it will correctly describe the dynamic properties of colloidal systems.

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“…The third important advancement is the derivation of Onsager-Fuoss expression of the concentration dependence of viscosity 37 . Expressions of Debye-Falkenhagen-Onsager-Fuoss (DFOF) limiting laws 38 , based on the Debye-Hückel (DH) ion pair distribution functions can efficiently describe the motion of ions in an electrolyte solution in terms of specific conductivity, diffusion and other rheological transport coefficients with their distinctive squareroot in concentration dependence at very low ion concentration (up to 10 -2 M) 39 . In addition, these laws provide elegant explanations of the different experimental observations on ion diffusion constant reported by QENS and NMR measurements 40 .…”

Section: Introductionmentioning

confidence: 99%

Mode coupling theory analysis of electrolyte solutions: Time dependent diffusion, intermediate scattering function, and ion solvation dynamics

Roy

Yashonath

Bagchi

2015

The Journal of Chemical Physics

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A self-consistent mode coupling theory (MCT) with microscopic inputs of equilibrium pair correlation functions is developed to analyze electrolyte dynamics. We apply the theory to calculate concentration dependence of (i) time dependent ion diffusion, (ii) intermediate scattering function of the constituent ions, and (iii) ion solvation dynamics in electrolyte solution. Brownian dynamics with implicit water molecules and molecular dynamics method with explicit water are used to check the theoretical predictions. The time dependence of ionic self-diffusion coefficient and the corresponding intermediate scattering function evaluated from our MCT approach show quantitative agreement with early experimental and present Brownian dynamic simulation results. With increasing concentration, the dispersion of electrolyte friction is found to occur at increasingly higher frequency, due to the faster relaxation of the ion atmosphere. The wave number dependence of intermediate scattering function, F(k, t), exhibits markedly different relaxation dynamics at different length scales. At small wave numbers, we find the emergence of a step-like relaxation, indicating the presence of both fast and slow time scales in the system. Such behavior allows an intriguing analogy with temperature dependent relaxation dynamics of supercooled liquids. We find that solvation dynamics of a tagged ion exhibits a power law decay at long times-the decay can also be fitted to a stretched exponential form. The emergence of the power law in solvation dynamics has been tested by carrying out long Brownian dynamics simulations with varying ionic concentrations. The solvation time correlation and ion-ion intermediate scattering function indeed exhibit highly interesting, non-trivial dynamical behavior at intermediate to longer times that require further experimental and theoretical studies.

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A unifying mode-coupling theory for transport properties of electrolyte solutions. II. Results for equal-sized ions electrolytes

Cited by 24 publications

References 76 publications

Dynamics of suspensions of hydrodynamically structured particles: analytic theory and applications to experiments

Dynamics of suspensions of hydrodynamically structured particles: analytic theory and applications to experiments

Long-time self-diffusion of charged spherical colloidal particles in parallel planar layers

Mode coupling theory analysis of electrolyte solutions: Time dependent diffusion, intermediate scattering function, and ion solvation dynamics

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