2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 7: Yang Intl. Symp. / Multiscale Material Mechanics

Editors:Kongoli F, Aifantis E, Wang H, Zhu T
Publisher:Flogen Star OUTREACH
Publication Year:2016
Pages:190 pages
ISBN:978-1-987820-48-5
ISSN:2291-1227 (Metals and Materials Processing in a Clean Environment Series)
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    Surface Effect on Mechanical Properties and Local Mobility of Ultrathin Polystyrene Films from Molecular Dynamics Simulations

    Fan Yang1; Zheng Zhong1;
    1TONGJI UNIVERSITY, Shanghai, China;
    Type of Paper: Regular
    Id Paper: 491
    Topic: 1

    Abstract:

    Thin polystyrene (PS) film has shown anomalous properties such as reduced glass transition temperature when the thickness is below 100 nm. However, few attentions have been paid to its mechanical properties, which are important in understanding the stability and reliability of polymer nano-structures. In this work, we aim at elucidating the size dependent mechanical properties of ultrathin polystyrene films using molecular dynamics (MD) simulations. Coarse grained MD samples of free-standing PS films with different thicknesses were generated using the augmented phantom chain growth method. Active deformations were applied by moving two repulsive walls to determine the size dependent mechanical properties of the films. The distribution of local atomic mobility was investigated through dividing the films into equidistant bins along thickness and calculating the mean square displacement (MSD) for each bin. The local mobility of atoms at different positions of the chain as well as the mobility of the entire chain are also investigated. The results indicate the existence of a softened surface layer with reduced modulus and enhanced local atom mobility compared to the bulk state. It shows the deformation has an enhancing effect on the local atom mobility, especially along the thickness direction. This work can provide insights into the size dependent mechanical properties of ultrathin PS films.

    Keywords:

    Deformation; Dynamics; Films; Mechanics; Nanomaterials; Polymer; Surface;

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    Cite this article as:

    Yang F and Zhong Z. Surface Effect on Mechanical Properties and Local Mobility of Ultrathin Polystyrene Films from Molecular Dynamics Simulations. In: Kongoli F, Aifantis E, Wang H, Zhu T, editors. Sustainable Industrial Processing Summit SIPS 2016 Volume 7: Yang Intl. Symp. / Multiscale Material Mechanics. Volume 7. Montreal(Canada): FLOGEN Star Outreach. 2016. p. 163-170.