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arXiv · 2007.12155

Energy barriers and cooperative motion at the surface of freestanding glassy polystyrene films

Derek Fujimoto·W. Andrew MacFarlane·Joerg Rottler
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Abstract

We investigate the near-surface relaxation of freestanding atactic \glsdesc{ps} films with molecular dynamics simulations. As in previous coarse-grained simulations, relaxation times for backbone segments and phenyl rings are linked to their bulk relaxation times via a power law coupling relation. Variation of the coupling exponent with distance from the surface is consistent with depth-dependent activation barriers. We also quantify a reduction of dynamical heterogeneity at the interface which can be interpreted in the framework of cooperative models for glassy dynamics.

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Derek Fujimoto, W. Andrew MacFarlane, Joerg Rottler. 2020-07-23. Energy barriers and cooperative motion at the surface of freestanding glassy polystyrene films. https://doi.org/10.1063/5.0022958

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