Molecular Dynamics Simulation of Solvent-Polymer Interdiffusion. I. Fickian diffusion

The interdiffusion of a solvent into a polymer melt has been studied using large scale molecular dynamics and Monte Carlo simulation techniques. The solvent concentration profile and weight gain by the polymer have been measured as a function of time. The weight gain is found to scale as t^{1/2}, which is expected for Fickian type of diffusion. The concentration profiles are fit very well assuming Fick's second law with a constant diffusivity. The diffusivity found from fitting Fick's second law is found to be independent of time and equal to the self diffusion constant in the dilute solvent limit. We separately calculated the diffusivity as a function of concentration using the Darken equation and found that the diffusivity is essentially constant for the concentration range relevant for interdiffusion.Comment: 17 pages and 7 figure

Simulation multi-échelles de matériaux polymères : challenges à relever.

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De la molecule à la propriété – la simulation moléculaire.

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Multiscale modelling of polymer materials. Recent Advances and challenges.

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Calculation of the surface tension of water 40 years of molecular simulations

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Importance of the tail corrections on surface tension of curved liquid-vapor interfaces

International audienceWe report molecular simulations of the liquid-vapor cylindrical interface of methane. We apply the truncated Lennard-Jones potential and specific long-range corrections for the surface tension developed especially for cylindrical interfaces. We investigate the impact of the cutoff on the radial density profile, the intrinsic and long-range correction parts to the surface tension, and Tolman length. We also study the curvature dependence of the surface tension as a function of the cutoff used. In this work we shed light that both density and Tolman length are cutoff-dependent whereas the total surface tension is slightly curvature and cutoff dependent. © 2017 Author(s)

Size-effects on the surface tension near the critical point Monte Carlo simulations of the Lennard-Jones fluid

International audienceWe report Monte Carlo (MC) simulations of the Lennard-Jones (LJ) fluid at the liquid-vapor interface in the critical region. A slab-based tail method is associated with the MC simulations to approach as close as possible the critical point (T∗=0.98TC ∗). We investigate then the impact of system-sizes on the surface tension and coexisting densities by considering very large box dimensions for which the surface tension is independent of system-sizes at low temperatures

Structure and dynamics of the ionophore lasalocid. A multi-computational study. I. Gaseous state

Explorations of the conformational space of the ionophore lasalocid using a Monte-Carlo procedure, allowed the classification of the ionophore conformations into groups that differ in their hydrogen bonding systems. Semiempirical quantum calculations AM1 support these results, particularly those concerning the chelation systems. This conformational study was extended by some experiments involving rotations around the C-C bonds and by molecular dynamics simulations in the gas phase, to obtain open and totally unfolded conformations. The results confirm that lasalocid has a high degree of flexibility

A multi-scale modelling of an enzymatic PET degradation.

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