Gas Sorption and Barrier Properties of Polymeric Membranes from Molecular Dynamics and Monte Carlo Simulations

Cozmuta, Ioana; Blanco, Mario; Goddard, William A.

doi:10.1021/jp062942h

Cited by 55 publications

(34 citation statements)

References 16 publications

(29 reference statements)

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“…The AMBER (Assisted Model Building with Energy Refinement) [27], DREIDING [28], OPLS-AA (Optimized Potentials for Liquid Simulations -All Atom) [29] and CHARMM (Chemistry at HARvard Macromolecular Mechanics) [30] force fields have been successfully used to study polymeric systems [21,[31][32][33]. These models were therefore considered for the present study, and their validity were tested for the PE system studied here.…”

Section: Force Fieldmentioning

confidence: 99%

“…In contrast to experiments, where the permeation coefficient is determined from quantity of penetrant film thickness area time pressure drop across film (1) it is common in simulations [21,22] to determine the solubility coefficient [23], S, and diffusion coefficient, D, separately before calculating the permeation coefficient as,…”

Section: Introductionmentioning

confidence: 99%

“…Although it is possible to determine S using a variety of methods, including grand canonical Monte Carlo [24] (GCMC) and Henry's law method [21], the results presented below are obtained from the Gibbs ensemble Monte Carlo method [25,26] (GEMC). This method was selected since the long term aim of this research is to perform a systematic study of transport properties over a variety of polymers, including hydrophobic and hydrophilic systems, where a large range of penetrant concentration will be studied.…”

Section: Introductionmentioning

confidence: 99%

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Molecular modelling of oxygen and water permeation in polyethylene

Börjesson

Erdtman

Ahlström

et al. 2013

Polymer

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Abstract:Monte Carlo and molecular dynamics simulations were performed to calculate solubility, S, and diffusion, D, coefficients of oxygen and water in polyethylene, and to obtain a molecular-level understanding of the diffusion mechanism. The permeation coefficient, P, was calculated from the product of S and D. The AMBER force field, which yields the correct polymer densities under the conditions studied, was used for the simulations, and it was observed that the results were not sensitive to the inclusion of atomic charges in the force field. The simulated S for oxygen and water are higher and lower than experimental data, respectively. The calculated diffusion coefficients are in good agreement with experimental data. Possible reasons for the discrepancy in the simulated and experimental solubilities, which results in discrepancies in the permeation coefficients, are discussed. The diffusion of both penetrants occurs mainly by large amplitude, infrequent jumps of the molecules through the polymer matrix.

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Section: Force Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular modelling of oxygen and water permeation in polyethylene

Börjesson

Erdtman

Ahlström

et al. 2013

Polymer

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“…Later, de Pablo et al [22] employed Gibbs ensemble Monte Carlo simulations in order to compute the solubility of short chain alkanes in polyethylene melts beyond Henry's regime. Several studies have followed, considering many different penetrant gases and more complex polymers such as polystyrene [23], poly(styrene-alt-maleic anhydride) copolymer, pols-(styrene-stat-butadiene) rubber and atactic polystyrene [24], polyimide [25], polyamide [26], polyethylene terephthalate [27,28].…”

Section: Introductionmentioning

confidence: 99%

Gas Permeation in Semicrystalline Polyethylene as Studied by Molecular Simulation and Elastic Model

Memari

Lachet

Rousseau

2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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> Development of Reactive Barrier Polymers against Corrosion for the Oil and Gas Industry: From Formulation to Qualification through the Development of Predictive Multiphysics ModelingDéveloppement de matériaux barrières réactifs contre la corrosion pour l'industrie pétrolière : de la formulation à la qualification industrielle en passant par le développement de modèles multiphysiques prédictifs Résumé -Perméation de gaz dans le polyéthylène semi-cristallin par simulation moléculaire et modèle élastique -Dans ce travail, nous utilisons la simulation moléculaire pour étudier la perméa-tion de deux gaz (CH 4 et CO 2 ) dans le polyéthylène. Ces simulations sont conduites à des températures inférieures à la température de fusion du polymère. Bien que dans de telles conditions, le polyéthylène soit à l'état semi-cristallin, des boîtes de simulation contenant exclusivement du polymère amorphe sont utilisées. Dans de précédents travaux [Memari P., Lachet V., Rousseau B. (2010) Polymer 51, 4978], nous avons montré que les effets de la morphologie complexe des matériaux semi-cristallins pouvaient être pris en compte de manière implicite par une contrainte ad-hoc exercée sur la phase amorphe. Dans le présent travail, nous montrons que cette approche peut être mise en oeuvre non seulement pour le calcul de propriétés d'équilibre mais également pour le calcul de propriétés de transport comme les coefficients de diffusion. De plus, en utilisant le modèle élastique de Michaels et Hausslein [Michaels A.S., Hausslein R.W. (1965) J. Polymer Sci. : Part C 10, 61], cette contrainte ad-hoc peut être reliée à la fraction de chaînes qui contribuent au terme d'énergie élastique dans le matériau. Nous constatons que les propriétés de transport dans les régions amorphes sont fortement influencées par cette fraction de chaînes. Abstract

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“…A plasticizer agent di-octyl adipate (DOA) is added (40% by weight) to the binder to improve casting properties. To determine the conformational state of the polymer at 300 K and 1 atm pressure, we used the cohesive energy density (CED) Monte Carlo method 19,20 designed to predict accurate cohesive energy densities of polymers (CED combines repeated cycles of temperature annealing and quenching simultaneous with density annealing and quenching to ensure that polymer chains are fully equilibrated). We used CED to build ten independent samples of each polymer within a unit cell containing two independent molecular chains and eight DOA molecules.…”

mentioning

confidence: 99%

Elucidation of the dynamics for hot-spot initiation at nonuniform interfaces of highly shocked materials

Zybin

Goddard

et al. 2011

Phys. Rev. B

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The fundamental processes in shock-induced instabilities of materials remain obscure, particularly for detonation of energetic materials. We simulated these processes at the atomic scale on a realistic model of a polymer-bonded explosive (3,695,375 atoms/cell) and observed that a hot spot forms at the nonuniform interface, arising from shear relaxation that results in shear along the interface that leads to a large temperature increase that persists long after the shock front has passed the interface. For energetic materials this temperature increase is coupled to chemical reactions that lead to detonation. We show that decreasing the density of the binder eliminates the hot spot. The interaction of shock waves with nonuniform interfaces plays an essential role in the interfacial instabilities in inertial confinement fusion (ICF), in shock-induced RichtmyerMeshkov instabilities (RMIs), and in detonation in heterogeneous polymer-bonded explosives (PBXs). For detonation, it is generally accepted that hot spots form during the development of instabilities as shock waves pass through the interface or other defects.1-4 Despite numerous experimental and theoretical studies, the fundamental processes involved remain controversial. This is due to the complex environment and coupling of thermal, chemical, and mechanical degree of freedom, which is extremely difficult to unravel experimentally. It has also been very difficult theoretically to include the reactive processes involved and yet cover the enormous size and time scales intrinsic to the phenomena.To discover the origin of shock-induced hot-spot formation, we carried out reactive dynamics (RD) using the ReaxFF reactive force field on a realistic model of a real polymerbonded explosive PBX N-106. Energetic materials (EMs) are essential for applications ranging from rocket engines, to building and dam construction, and to armaments. Generally the EM is bound together in a matrix of polymer elastomers to form the PBX that can be molded into various shapes, while providing some control in resisting unintentional detonation due to shocks or friction. Unfortunately, current generations of PBXs are sensitive to accidental detonation, despite many attempts to control the safety by improvements in materials and manufacturing practices. Here we use the ReaxFF reactive force field to examine the effect of shocks on realistic models of polymer-bonded explosives, where we use these simulations to extract the mechanism of hot-spot formation. Then, based on this model, we predict how to change the system to reduce the hot spot, and carry out simulations to validate this prediction.ReaxFF has now been established to provide nearly the accuracy of quantum calculation in the various reaction barriers and rates while providing a computational efficiency nearly that of ordinary molecular dynamics (MD) with ordinary force fields (FFs), enabling us to study the complex processes involved in interfacial instabilities at the atomic scale, providing insights on such phenomenon. Thus ReaxF...

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Gas Sorption and Barrier Properties of Polymeric Membranes from Molecular Dynamics and Monte Carlo Simulations

Cited by 55 publications

References 16 publications

Molecular modelling of oxygen and water permeation in polyethylene

Molecular modelling of oxygen and water permeation in polyethylene

Gas Permeation in Semicrystalline Polyethylene as Studied by Molecular Simulation and Elastic Model

Elucidation of the dynamics for hot-spot initiation at nonuniform interfaces of highly shocked materials

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