| Reference : Crystal nucleation mechanism in melts of short polymer chains under quiescent conditi... |
| Scientific journals : Article | |||
| Physical, chemical, mathematical & earth Sciences : Physics | |||
| http://hdl.handle.net/10993/18182 | |||
| Crystal nucleation mechanism in melts of short polymer chains under quiescent conditions and under shear flow | |
| English | |
Anwar, Muhammad  [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >] | |
| Berryman, Josh [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >] | |
| Schilling, Tanja [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >] | |
| 2014 | |
| Journal of Chemical Physics | |
| American Institute of Physics | |
| 141 | |
| 124910 | |
| Yes (verified by ORBilu) | |
| International | |
| 0021-9606 | |
| 1089-7690 | |
| New York | |
| NY | |
| [en] We present a molecular dynamics simulation study of crystal nucleation from undercooled melts
of n-alkanes, and we identify the molecular mechanism of homogeneous crystal nucleation under quiescent conditions and under shear flow. We compare results for n-eicosane (C20) and npentacontahectane (C150), i.e., one system below the entanglement length and one above, at 20%– 30% undercooling. Under quiescent conditions, we observe that entanglement does not have an effect on the nucleation mechanism. For both chain lengths, the chains first align and then straighten locally, then the local density increases and finally positional ordering sets in. At low shear rates the nucleation mechanism is the same as under quiescent conditions, while at high shear rates the chains align and straighten at the same time. We report on the effects of shear rate and temperature on the nucleation rates and estimate the critical shear rates, beyond which the nucleation rates increase with the shear rate. In agreement with previous experimental observation and theoretical work, we find that the critical shear rate corresponds to a Weissenberg number of order 1. Finally, we show that the viscosity of the system is not affected by the crystalline nuclei. | |
| University of Luxembourg: High Performance Computing - ULHPC | |
| http://hdl.handle.net/10993/18182 | |
| 10.1063/1.4896568 | |
| http://dx.doi.org/10.1063/1.4896568 |
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