Molecular Dynamics Simulation of Surface Nucleation during Growth of an Alkane Crystal
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ma2015-027572_ms.pdf
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Author(s)
Bourque, Alexander Jules
Rutledge, Gregory C
Date Issued
May 2016
Journal
Macromolecules
Publisher
American Chemical Society (ACS)
Citation
Bourque, Alexander et al. “Molecular Dynamics Simulation of Surface Nucleation During Growth of an Alkane Crystal.” Macromolecules 49, 9 (May 2016): 3619–3629 © 2016 American Chemical Society
Version
Author's final manuscript
Abstract
Crystal growth from the melt of n-pentacontane (C50) was studied by molecular dynamics simulation. Quenching below the melting temperature gives rise to propagation of the crystal growth front into the C50 melt from a crystalline polyethylene surface. By tracking the location of the crystal–melt interface, crystal growth rates between 0.02 and 0.05 m/s were observed, for quench depths of 10–70 K below the melting point. These growth rates compare favorably with those from a previous study by Waheed et al. [ Polymer 2005, 46, 8689−8702]. Next, surface nucleation was identified with the formation of two-dimensional clusters of crystalline sites within layers parallel to the propagating growth front. Critical nucleus sizes, waiting times, and rates for surface nucleation were estimated by a mean first passage time analysis. A surface nucleation rate of ∼0.05 nm⁻² ns⁻¹ was observed, and it was nearly temperature-independent. Postcritical “spreading” of the surface nuclei to form a completely crystallized layer slowed with deeper supercooling.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1021/acs.macromol.5b02757
