Detailed molecular simulations to investigate multicomponent diffusion models

Patel, Harshit A.; Garde, Shekhar; Nauman, E. Bruce

doi:10.1002/aic.10745

Cited by 4 publications

(2 citation statements)

References 16 publications

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“…E. Bruce Nauman's contributions to the field of phase behavior and processing of polymers have included studies of structure, thermodynamics, and dynamics. − More recently, his group has performed work employing molecular simulations to study interfacial and dynamic systems to which one of the authors (S.G.) has contributed. The study presented here is broadly motivated by those simulations of interfaces.…”

Section: Introductionmentioning

confidence: 99%

Structure, Stability, and Rupture of Free and Supported Liquid Films and Assemblies in Molecular Simulations

Godawat

Jamadagni

Errington

et al. 2008

Ind. Eng. Chem. Res.

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Attractive interactions between molecules lead to formation of the liquid phase at sufficiently low temperatures. In the absence of external fields or containers, liquids assume the shape of spherical drops, which minimize their surface area. In systems with 3-D periodic boundary conditions (PBCs), which are routinely employed in molecular simulations, alternate configurations can be stable depending on the extent of the system. The stability of a variety of structures under 3-D PBCs originates from the underlying variation of free energy with density as shown elegantly by MacDowell and co-workers (MacDowell, L. G.; Shen, V. K.; Errington, J. R. J. Chem. Phys. 2006, 125, 3.). Here we present analysis of extensive Monte Carlo and molecular dynamics simulations of Lennard-Jones and water fluids to calculate free energy and explore the phase diagram that governs formation of different liquid assemblies. We also study metastability of different shapes and their interconversions by systematically initializing simulations in various configurations. Further, We present results on the rupture of thin liquid films on solid substrates, with focus on the evolution of liquid structure and the rupture mechanism. Our estimates of important capillary wavelengths from simulations are in good agreement with theoretical predictions of Vrij and Overbeek (Vrij, A.; Overbeek, J. T. J. Am. Chem. Soc. 1968, 90, 3074−3078.). Collectively, our work significantly extends the previous simulation studies of interfacial systems, and especially of thin-film structure, stability, and rupture processes in molecular simulations.

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Section: Introductionmentioning

confidence: 99%

Structure, Stability, and Rupture of Free and Supported Liquid Films and Assemblies in Molecular Simulations

Godawat

Jamadagni

Errington

et al. 2008

Ind. Eng. Chem. Res.

Self Cite

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“…Instead, we choose a simple and robust model that accounts for the fluxes of all components, that avoids anomalous behavior, and perhaps most importantly, allows simple and even constant estimates of diffusion coefficients that are allowed to differ by orders of magnitude. The proportional flux method6 has been tested using molecular dynamics for the diffusion of short‐chain alkanes 12. In the following part the proportional flux model is applied to spinodal decomposition in ternary, asymmetric systems of polymers and solvents.…”

Section: Introductionmentioning

confidence: 99%

Spinodal Decomposition in Ternary Systems with Significantly Different Component Diffusivities

Alfarraj

Nauman

2007

Macro Theory & Simulations

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A numerical method for simulating spinodal decomposition in ternary systems with order‐of‐magnitude differences in diffusion coefficients is presented. The method has been partially verified by molecular dynamic simulations and gives results equivalent to the standard technique when the diffusivities are equal. A two‐dimensional simulation of an asymmetric polymer/polymer/polymer system reproduces an experimentally observed bimodal distribution of dispersed‐phase particle sizes. The ripening exponent for the larger particles is near the expected value of 0.33, but that for the smaller particles is only about 0.1. The method was also used for a polymer/polymer/solvent system.magnified image

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Thermodynamic driving force for diffusion: Comparison between theory and simulation

Whitman¹,

Aranovich²,

Donohue³

2011

The Journal of Chemical Physics

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In previous work, lattice density functional theory equations have been recast into differential form to determine a property whose gradient is universally proportional to the diffusive flux. For color counter diffusion, this property appears as the impingement rate onto vacancies and molecules of a species whose density gradient can be influenced by diffusion. Therefore, the impingement rate of a diffusing molecule depends on the mobility of its surroundings. In order to determine the validity of this finding, molecular dynamics simulations of color counter diffusion were performed in which the mobility of the solvent was varied to determine if the flux of the diffusing species responded to the change when all other factors, such as density gradient, available volume, and temperature are held constant.

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Detailed molecular simulations to investigate multicomponent diffusion models

Cited by 4 publications

References 16 publications

Structure, Stability, and Rupture of Free and Supported Liquid Films and Assemblies in Molecular Simulations

Structure, Stability, and Rupture of Free and Supported Liquid Films and Assemblies in Molecular Simulations

Spinodal Decomposition in Ternary Systems with Significantly Different Component Diffusivities

Thermodynamic driving force for diffusion: Comparison between theory and simulation

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