Structure and Dynamics of a Graphene Melt.

Published on May 22, 2018in ACS Nano14.588
· DOI :10.1021/ACSNANO.8B00524
Wenjie Xia20
Estimated H-index: 20
(NIST: National Institute of Standards and Technology),
Fernando Vargas-Lara10
Estimated H-index: 10
(NIST: National Institute of Standards and Technology)
+ 1 AuthorsJack F. Douglas91
Estimated H-index: 91
(NIST: National Institute of Standards and Technology)
We explore the structural and dynamic properties of bulk materials composed of graphene nanosheets using coarse-grained molecular dynamics simulations. Remarkably, our results show clear evidence that bulk graphene materials exhibit a fluid-like behavior similar to linear polymer melts at elevated temperatures and that these materials transform into a glassy-like “foam” state at temperatures below the glass-transition temperature (Tg) of these materials. Distinct from an isolated graphene sheet, which exhibits a relatively flat shape with fluctuations, we find that graphene sheets in a melt state structurally adopt more “crumpled” configurations and correspondingly smaller sizes, as normally found for ordinary polymers in the melt. Upon approaching the glass transition, these two-dimensional polymeric materials exhibit a dramatic slowing down of their dynamics that is likewise similar to ordinary linear polymer glass-forming liquids. Bulk graphene materials in their glassy foam state have an exceptionally...
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