Contribution of inter- and intramolecular energy transfers to heat conduction in liquids

Torii, Daichi; Nakano, T.; Ohara, Taku

doi:10.1063/1.2821963

Cited by 87 publications

(58 citation statements)

References 15 publications

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“…It has also been successfully applied to MD simulation of heat conduction. For example, thermal conductivity of n-octane bulk liquid reproduced by the NERD model, a model represented by the united atom model, has been reported (13) , which agrees well with experimental results within the difference of approximately 15%. Thus, the united atom model is the standard choice to reproduce lipid bilayer by MD simulation and to simulate heat conduction in that, which justifies the present method of simulation.…”

Section: Molecular Dynamics Simulationssupporting

confidence: 75%

“…Three-and fourbody potentials are applied for some intramolecular interactions for bending and torsional deformation of molecules. The total energy flux, Jx, in the direction of x axis that passes through the control surface which is perpendicular to the thermal energy flux is measured in the present system as follows (13,16) , (for the four-body potentials). x ij is the distance along the x axis between sites i and j. N ij and ω i are the torque vector acting on molecule i due to its interaction with molecule j, and angular velocity vector of molecule i, respectively.…”

Section: Calculation Of Thermal Energy Fluxmentioning

confidence: 99%

“…For the general form of the formula and its theoretical background, see Ref. (13). In the present study, two-body potentials are applied for all the intermolecular interactions and some of the intramolecular interactions.…”

Section: Calculation Of Thermal Energy Fluxmentioning

confidence: 99%

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Study on Molecular Thermal Energy Transfer in a Lipid Bilayer

Nakano

Ohara

Kikugawa

2008

JTST

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Recently, lipid bilayers attract a great deal of interest as a material with nanoscale structure. Various devices utilizing lipid bilayers, which include some kinds of sensors and molecular sorting devices, have been proposed. Understanding of thermal energy transfer in the lipid bilayers is important for utilizing the lipid bilayers as a new material for NEMS with nano structures. In this study, we have investigated the energy transfer along and across the bilayer membrane by molecular dynamics simulations of the lipid bilayer in liquid water. We found that along the bilayer membrane, thermal energy flux in the lipid bilayer is much smaller than that in the water layer. On the other hand, in case of thermal energy transfer across the membrane, total thermal resistance of the lipid bilayer-water system is composed of thermal resistances of various parts of the system, including water layer, head group of lipid, and tail hydrocarbon chain of lipid, which exhibit different magnitude of values. It is found that the tail hydrocarbon chains of lipid have the highest thermal resistance.

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Section: Molecular Dynamics Simulationssupporting

confidence: 75%

Section: Calculation Of Thermal Energy Fluxmentioning

confidence: 99%

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Study on Molecular Thermal Energy Transfer in a Lipid Bilayer

Nakano

Ohara

Kikugawa

2008

JTST

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“…For polymer liquids represented by molecular models with multibody potentials, such as those for bending and torsional deformations of molecules, a molecular dynamics expression for the macroscopic heat flux has been developed [13]. In this case, energy transfer in a molecule via the deformation of the molecule.…”

Section: Introductionmentioning

confidence: 99%

Molecular Heat Transfer in Lipid Bilayers With Symmetric and Asymmetric Tail Chains

Nakano¹,

Kikugawa²,

Ohara

2013

Journal of Heat Transfer

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Intramolecular energy transfer in polymer molecules plays a dominant role in heat conduction in polymer materials. In soft matter where polymer molecules form an ordered structure, the intramolecular energy transfer works in an anisotropic manner, which results in an anisotropic thermal conductivity. Based on this idea, thermal energy transfer in lipid bilayers, a typical example ofsofi matter, has been analyzed in the present study. Nonequilibrium molecular dynamics simulations were carried out on single component lipid bilayers with ambient water. In the simulations, dipalmitoyl-phosphatidyl-clioline (DPPC), dilauroyl-phosphatidyl-choline (DLPC), and stearoyl-myristoyl-phosphatidyl-choline (SMPC), which have two alkyl chains with 16C atoms for each, 12 C atoms for each, and 18 and 14 C atoms, respectively, were used as lipid molecules. The thermal energy transfer has been decomposed to inter-and intramolecular energy transfer between individual molecules or molecular sites, and its characteristics were discussed. In the case of heat conduction in the direction across the membranes (cross-plane heat conduction), the highest thermal resistance exists at the center of the lipid bilayer, where lipid alkyl chains face each other. The asymmetric chain length of SMPC reduces this thermal resistance at the interface between lipid monolayers. The cross-plane thermal conductivities of lipid ntonolayers are 4.8-6.5 times as high as the ones in the direction parallel to the membranes (inplane) for the cases of the tested lipids. The overall cross-plane thermal conductivities of the lipid bilayers are reduced to be approximately half of those of the monolayers, due to the thermal resistance at the interfaces between two monolayers. The lipid bilayer of SMPC with tail chains of asymmetric length exhibits the highest cross-plane thermal conductivity. These results provide detailed information about the transport characteri.'itics of thermal energy in soft matter, which are new materials with design flexibility and biocompatibility. The results lead to their design to realize desired thermophysical properties and functions.

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“…8 When using the Green-Kubo relation in atomistic systems including angle and torsion potentials, we must start with a microscopic definition of the energy flow of three-and four-body potentials. 9 Much longer simulation runs are needed to obtain an accurate correlation function. The development of a general program code for calculating the energy flow of an atomistic chemical system is a heavy task.…”

Section: Introductionmentioning

confidence: 99%

Ordering simulation of high thermal conductivity epoxy resins

Koda

Toyoshima

Tokutaro

et al. 2012

Polym J

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In this work, we performed molecular dynamics simulations of liquid-crystalline epoxy resins using the simulation system OCTA in combination with J-OCTA. One molecule was modeled as a diamine, the ends of which are connected to derivatives of diepoxy mesogens. The number of molecules in the system was eight for the present simulation. The molecular ends were drawn by an external force in order to generate a well-aligned initial structure. We relaxed the system after removing the external force and calculated statistical average. The results exhibited an even-odd effect of density and alignment order for the number of methylene units in the mesogenic structure. The obtained alignment order of the epoxy molecules showed a strong correlation with the experimentally obtained thermal conductivity. Finally, we proposed a protocol for using the present simulation to screen for epoxy molecules of higher thermal conductivity.

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Contribution of inter- and intramolecular energy transfers to heat conduction in liquids

Cited by 87 publications

References 15 publications

Study on Molecular Thermal Energy Transfer in a Lipid Bilayer

Study on Molecular Thermal Energy Transfer in a Lipid Bilayer

Molecular Heat Transfer in Lipid Bilayers With Symmetric and Asymmetric Tail Chains

Ordering simulation of high thermal conductivity epoxy resins

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