scholarly journals Thermal Conductivity of Polyamide-6,6/Carbon Nanotube Composites: Effects of Tube Diameter and Polymer Linkage between Tubes

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1465 ◽  
Author(s):  
Mahboube Keshtkar ◽  
Nargess Mehdipour ◽  
Hossein Eslami
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Polymer Chains ◽  
Nonequilibrium Molecular Dynamics ◽  
Interfacial Thermal Resistance ◽  
Conductivity Anisotropy ◽  
Nanotube Composites ◽  
Dynamics Simulations ◽  
Effect Of Surface

Reverse nonequilibrium molecular dynamics simulations were done to quantify the effect of the inclusion of carbon nanotubes (CNTs) in the Polyamide-6,6 matrix on the enhancement in the thermal conductivity of polymer. Two types of systems were simulated; systems in which polymer chains were in contact with a single CNT, and those in which polymer chains were in contact with four CNTs, linked together via polymer linkers at different linkage fractions. In both cases, heat transfer in both perpendicular and parallel (to the CNT axis) directions were studied. To examine the effect of surface curvature (area) on the heat transfer between CNT and polymer, systems containing CNTs of various diameters were simulated. We found a large interfacial thermal resistance at the CNT-polymer boundary. The interfacial thermal resistance depends on the surface area of the CNT (lower resistances were seen at the interface of flatter CNTs) and is reduced by linking CNTs together via polymer chains, with the magnitude of the reduction depending on the linkage fraction. The thermal conductivity of polymer in the perpendicular direction depends on the surface proximity; it is lower at closer distances to the CNT surface and converges to the bulk value at distances as large as 2 nm. The chains at the interface of CNT conduct heat more in the parallel than in the perpendicular directions. The magnitude of this thermal conductivity anisotropy reduces with decreasing the CNT diameter and increasing the linkage fraction. Finally, microscopic parameters obtained from simulations were used to investigate macroscopic thermal conductivities of polymer nanocomposites within the framework of effective medium approximation.

Investigation of Interfacial Thermal Resistance on Nano-Structures Using Molecular Dynamics Simulations

2010 ◽  
Author(s):  
Navdeep Singh ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Resistance ◽  
Md Simulations ◽  
Interfacial Thermal Resistance ◽  
Filler Materials ◽  
Nano Structures ◽  
Dynamics Simulations ◽  
Very High

Due to their very high thermal conductivity carbon nanotubes have been found to be an excellent material for thermal management. Experiments have shown that the heaters coated with carbon nanotubes increase the heat transfer by as much as 60%. Also when nanotubes are used as filler materials in composites, they tend to increase the thermal conductivity of the composites. But the increase in the heat transfer and the thermal conductivity has been found to be much less than the calculated values. This decrease has been attributed to the interfacial thermal resistance between the carbon nanotubes and the surrounding material. MD simulations were performed to study the interfacial thermal resistance between the carbon nanotubes and the liquid molecules. In the simulations, the nanotube is placed at the center of the simulation box and a temperature of 300K is imposed on the system. Then the temperature of the nanotube is raised instantaneously and the system is allowed to relax. From the temperature decay, the interfacial thermal resistance between the carbon nanotube and the liquid molecules is calculated. In this study the liquid molecules under investigation are n-heptane, n-tridecane and n-nonadecane.

Thermal conductivity and interfacial Thermal Resistance Behavior for the Polyaniline (C3N)– boron carbide (BC3) Heterostructure

2021 ◽  
Author(s):  
Arian Mayelifartash ◽  
Mohammad Ali Abdol ◽  
Sadegh Sadeghzadeh
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Resistance ◽  
Boron Carbide ◽  
Molecular Dynamics Simulations ◽  
Thermal Conductance ◽  
Interfacial Thermal Resistance ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations ◽  
Non Equilibrium

In this paper, by employing non-equilibrium molecular dynamics simulations (NEMD), the thermal conductance of hybrid formed by polyaniline (C3N) and boron carbide (BC3) in both armchair and zigzag configurations has...

Molecular Dynamics Study of Interfacial Thermal Resistance of Mercapto-Alkanol Self-Assembled Monolayer and Water

2009 ◽  
Author(s):  
Touru Kawaguchi ◽  
Gota Kikugawa ◽  
Ikuya Kinefuchi ◽  
Taku Ohara ◽  
Shinichi Yatuzuka ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bond ◽  
Thermal Resistance ◽  
Chem Phys ◽  
Nonequilibrium Molecular Dynamics ◽  
Interfacial Thermal Resistance ◽  
Water Molecules ◽  
Self Assembled Monolayer ◽  
Self Assembled ◽  
Dynamics Simulations

The interfacial thermal resistance of 11-mercaptoundecanol (-S(CH2)11OH) self-assembled monolayer (SAM) adsorbed on Au(111) substrate and water was investigated using nonequilibrium molecular dynamics simulations. The interfacial thermal resistance was found to be a half of that in the system which consists of 1-dodecanthiol (-S(CH2)11CH3) SAM adsorbed on Au(111) and toluene [Kikugawa G. et al., J. Chem. Phys. (2009)]. The effective thermal energy transfer originates from hydrogen-bond structure between the SAM and water molecules in spite of weak structurization of water molecules near the SAM surface.

Effect of Alkyl Chain Length on Molecular Heat Transfer Characteristics in Lipid Bilayers

2011 ◽  
Author(s):  
Takeo Nakano ◽  
Gota Kikugawa ◽  
Taku Ohara
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Lipid Bilayers ◽  
Chain Length ◽  
Phosphatidyl Choline ◽  
Acyl Chain ◽  
Nonequilibrium Molecular Dynamics ◽  
Acyl Chain Length ◽  
Acyl Chains ◽  
Dynamics Simulations

Nonequilibrium molecular dynamics simulations are carried out on single component lipid bilayers with ambient water in order to investigate the effect of acyl chain length on heat transport characteristics along and across the membranes. In this study, dipalmitoyl-phosphatidyl-choline (DPPC), dilauroyl-phosphatidyl-choline (DLPC), and stearoyl-myristoyl-phosphatidyl-choline (SMPC) which has two acyl chains of both sixteen C atoms, both twelve C atoms, and eighteen and fourteen C atoms, respectively, were used as lipid molecules. In the direction along the membranes, thermal conductivity corresponds with that of each membrane. On the other hand, in the direction across membrane, the highest thermal resistance exists at the center of lipid bilayer where lipid acyl chains face each other. However, asymmetric chain length reduces thermal resistance at the interface between lipid monolayers. Therefore, thermal conductivity across the membrane which consists of asymmetric chain length is higher than those which consist of symmetric chain length.

scholarly journals Interfacial Modulation of Graphene by Polythiophene with Controlled Molecular Weight to Enhance Thermal Conductivity

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 895
Author(s):  
Ya Li ◽  
Yu Wang ◽  
Peng Chen ◽  
Ru Xia ◽  
Bin Wu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Molecular Weight ◽  
Thermal Resistance ◽  
Vinylidene Fluoride ◽  
Interfacial Thermal Resistance ◽  
Heat Accumulation ◽  
Π Interactions ◽  
Molecular Weights ◽  
Thermally Conductive

With a trend of continuing improvement in the development of electronic devices, a problem of serious heat accumulation has emerged which has created the need for more efficient thermal management. Graphene sheets (GNS) have drawn much attention with regard to heat transfer because of their excellent in-plane thermal conductivity; however, the ultrahigh interfacial thermal resistance between graphene lamellae has seriously restricted its practical applications. Herein, we describe heat transfer membranes composed of graphene which have been modified by intrinsic thermally conductive polymers with different molecular weights. The presence of macromolecular surface modifiers not only constructed the graphene heat transfer interface by π–π interactions, but also significantly enhanced the membranes’ in-plane thermal conductivity by utilizing their intrinsic heat transfer properties. Such results indicated that the in-plane thermal conductivity of the fabricated membrane exhibits a high in-plane thermal conductivity of 4.17 W m−1 K−1, which, containing the GNS modified with 6000 g/mol (Mn) of poly(3-hexylthiophene) (P3HT), was 26 times higher that of poly (vinylidene fluoride) (PVDF). The P3HT molecular chain with specific molecular weight can form more matching structure π–π interactions, which promotes thermal conductivity. The investigation of different molecular weights has provided a new pathway for designing effective interfacial structures to relieve interface thermal resistance in thermally conductive membranes.

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