TY - JOUR
T1 - Heat conduction in chain polymer liquids
T2 - Molecular dynamics study on the contributions of inter- and intramolecular energy transfer
AU - Ohara, Taku
AU - Yuan, Tan Chia
AU - Torii, Daichi
AU - Kikugawa, Gota
AU - Kosugi, Naohiro
N1 - Funding Information:
This work has been supported by the Global COE “Flow Dynamics” and Grant-in-Aid for Scientific Research by the Japan Society for the Promotion of Science (JSPS). All calculations were performed on the SGI Altix 3700B at the Advanced Fluid Information Research Center, Institute of Fluid Science, Tohoku University. The authors thank the reviewers of the manuscript for the helpful suggestions.
PY - 2011/7/21
Y1 - 2011/7/21
N2 - In this paper, the molecular mechanisms which determine the thermal conductivity of long chain polymer liquids are discussed, based on the results observed in molecular dynamics simulations. Linear n-alkanes, which are typical polymer molecules, were chosen as the target of our studies. Non-equilibrium molecular dynamics simulations of bulk liquid n-alkanes under a constant temperature gradient were performed. Saturated liquids of n-alkanes with six different chain lengths were examined at the same reduced temperature (0.7T c), and the contributions of inter- and intramolecular energy transfer to heat conduction flux, which were identified as components of heat flux by the authors' previous study J. Chem. Phys. 128, 044504 (2008)10.1063/1.2821963, were observed. The present study compared n-alkane liquids with various molecular lengths at the same reduced temperature and corresponding saturated densities, and found that the contribution of intramolecular energy transfer to the total heat flux, relative to that of intermolecular energy transfer, increased with the molecular length. The study revealed that in long chain polymer liquids, thermal energy is mainly transferred in the space along the stiff intramolecular bonds. This finding implies a connection between anisotropic thermal conductivity and the orientation of molecules in various organized structures with long polymer molecules aligned in a certain direction, which includes confined polymer liquids and self-organized structures such as membranes of amphiphilic molecules in water.
AB - In this paper, the molecular mechanisms which determine the thermal conductivity of long chain polymer liquids are discussed, based on the results observed in molecular dynamics simulations. Linear n-alkanes, which are typical polymer molecules, were chosen as the target of our studies. Non-equilibrium molecular dynamics simulations of bulk liquid n-alkanes under a constant temperature gradient were performed. Saturated liquids of n-alkanes with six different chain lengths were examined at the same reduced temperature (0.7T c), and the contributions of inter- and intramolecular energy transfer to heat conduction flux, which were identified as components of heat flux by the authors' previous study J. Chem. Phys. 128, 044504 (2008)10.1063/1.2821963, were observed. The present study compared n-alkane liquids with various molecular lengths at the same reduced temperature and corresponding saturated densities, and found that the contribution of intramolecular energy transfer to the total heat flux, relative to that of intermolecular energy transfer, increased with the molecular length. The study revealed that in long chain polymer liquids, thermal energy is mainly transferred in the space along the stiff intramolecular bonds. This finding implies a connection between anisotropic thermal conductivity and the orientation of molecules in various organized structures with long polymer molecules aligned in a certain direction, which includes confined polymer liquids and self-organized structures such as membranes of amphiphilic molecules in water.
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U2 - 10.1063/1.3613648
DO - 10.1063/1.3613648
M3 - Article
C2 - 21787013
AN - SCOPUS:79960900080
VL - 135
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 3
M1 - 034507
ER -