A Computational Model for Nano Scale Cavities in the Atomic Structure of Polymer Melt and Comparisons to PALS

Dušan Račko

doi:10.4028/www.scientific.net/MSF.666.15

Paper Titles

Preface/Committees

Electron and Positron Densities for Mono Vacancy in SiC
p.1

Influence of Electron-Electron Correlations and Lattice Effects on Positron-Electron Enhancement Factors
p.5

The Distribution of Slowing-Down Times of Positrons Emitted from ²²Na and ⁶⁸Ge\⁶⁸Ga Isotopes into Metals
p.10

A Computational Model for Nano Scale Cavities in the Atomic Structure of Polymer Melt and Comparisons to PALS
p.15

Calculation of Gamma Spectra for Positron Annihilation on Molecules
p.21

Investigation of Resonances in the Scattering of a Heavy ‘Positron’ by H₂ that Involve Vibrationally Excited Quasi-Bound States
p.25

Positron Annihilation Characteristics in Superstrong Magnetic Fields
p.31

HomeMaterials Science ForumMaterials Science Forum Vol. 666A Computational Model for Nano Scale Cavities in...

A Computational Model for Nano Scale Cavities in the Atomic Structure of Polymer Melt and Comparisons to PALS

Abstract:

In the Present Contribution the Atomistic Structure of the Polymer Melt at 300 K Is Simulated by Means of Molecular Dynamics. the Agreement with an Experimental Density Is Obtained with a Deviation Lower than 1%. the Free Volume Is Analyzed in 1,000 Structures and 6.5 X 108 Cubic Å of Molecular Space. a Model for the Free Volume Cavities Is Proposed. in the Model the Size and Number of the Cavities Can Be Scaled by Three Parameters: Probe Radius, Cavity Depth and Cavity Threshold Volume. the Experimental Values of the Nano-Sized Cavity Volumes as Well as Ortho-Positronium Lifetimes Are Obtained, as Compared to Models with Cylindrical and Spherical Geometry. a Typical Value of the Number Density of Free Volume Cavities at 0.001 Å-3 Is Obtained. the Cavities Have Typically Elongated Shape with a Side-to-Length Ratio 1:2.

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Periodical:

Materials Science Forum (Volume 666)

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15-20

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.666.15

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Online since:

December 2010

Authors:

Dušan Račko

Keywords:

Free Volume, Molecular Dynamic (MD), Polymer Melt, Positron Annihilation, Simulation

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