scholarly journals Numerical Investigation of the Effect of Chirality of Carbon Nanotube on the Interfacial Thermal Resistance

2013 ◽  
Vol 2 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Yuzhu Hu ◽  
Debjyoti Banerjee
Nanoscale ◽  
2017 ◽  
Vol 9 (9) ◽  
pp. 3133-3139 ◽  
Author(s):  
Zheng Duan ◽  
Danyang Liu ◽  
Guang Zhang ◽  
Qingwei Li ◽  
Changhong Liu ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jungkyu Park ◽  
Vikas Prakash

In the present study, reverse nonequilibrium molecular dynamics is employed to study thermal resistance across interfaces comprising dimensionally mismatched junctions of single layer graphene floors with (6,6) single-walled carbon nanotube (SWCNT) pillars in 3D carbon nanomaterials. Results obtained from unit cell analysis indicate the presence of notable interfacial thermal resistance in the out-of-plane direction (along the longitudinal axis of the SWCNTs) but negligible resistance in the in-plane direction along the graphene floor. The interfacial thermal resistance in the out-of-plane direction is understood to be due to the change in dimensionality as well as phonon spectra mismatch as the phonons propagate from SWCNTs to the graphene sheet and then back again to the SWCNTs. The thermal conductivity of the unit cells was observed to increase nearly linearly with an increase in cell size, that is, pillar height as well as interpillar distance, and approaches a plateau as the pillar height and the interpillar distance approach the critical lengths for ballistic thermal transport in SWCNT and single layer graphene. The results indicate that the thermal transport characteristics of these SWCNT-graphene hybrid structures can be tuned by controlling the SWCNT-graphene junction characteristics as well as the unit cell dimensions.


Author(s):  
Tad Whiteside ◽  
Marie A. Priest ◽  
Clifford W. Padgett

In this paper, the effect on the interfacial thermal resistance between a composite system composed of a carbon nanotube or diamond nanorod and an octane matrix by the functionalization of those nanostructures with alkyl chains has been examined using molecular dynamics simulations. The effect of functionalization was studied by varying the percent functionalization from 0.00% to 2.00% using octyl as the functional group. As the percent functionalization increased, both systems showed a decrease in the interfacial thermal resistance. At 1.00% functionalization, as the alkyl chain length was increased from one to eight atoms, the interfacial thermal resistance of the carbon nanotube systems decreased to a minimum, while in the diamond nanorod system the interfacial thermal resistance remained constant.


2020 ◽  
Vol 24 (2 Part A) ◽  
pp. 745-756
Author(s):  
Bo Shi ◽  
Han Zhang ◽  
Jin Zhang

The vertical carbon nanotube arrays (VACNT), as a result of its flexibility and axial high thermal conductivity, exert a huge potential and play an increasingly important role in thermal interface materials. This paper proposed a model which can predict the contact thermal resistance of VACNT. The contact thermal resistance of VACNT under different pressures is calculated and compared with the experimental data. Also, the effect of variations in the surface roughness and VACNT parameters on the contact thermal resistance is investigated. Results show that the theoretical results are in good agreement with the experimental data. The contact thermal resistance is composed of interfacial thermal resistance, constriction thermal resistance, and VACNT resistance. Among which the interfacial thermal resistance is the major thermal resistance. The variations in VACNT length and diameter can change the bending degree of VACNT under the same pressure, which presents important implications on contact thermal resistance and can be used to optimize the contact thermal resistance of VACNT. The surface roughness exerts little effect on contact thermal resistance.


Author(s):  
Daniel J. Rogers ◽  
Jianmin Qu ◽  
Matthew Yao

The interfacial thermal resistance (ITR) between a carbon nanotube (CNT) and adjoining carbon, silicon, or copper substrate is investigated through non-equilibrium molecular dynamics simulation (NEMD). The theoretical phonon transmission also is calculated using a simplified form of the diffuse mismatch model (DMM) with direct simulation of the phonon density of states (DOS) under quasi-harmonic approximation. The results of theory and simulation are reported as a function of temperature in order to estimate the importance of anharmonicity and inelastic scattering. At 300K, the thermal conductance of CNT-substrate interfaces is ∼1500 W/mm2K for diamond carbon, ∼500 W/mm2K for silicon, and ∼250 W/mm2K for copper.


Author(s):  
Jungkyu Park ◽  
Vikas Prakash

We present results of a molecular dynamics study to analyze thermal transport at carbon nanotube (CNT)-graphene junctions comprising of single layer graphene and (6,6) armchair single-walled carbon nanotubes (SWCNTs). Two possible junction types with different degrees of sp2 and sp3 hybridization are investigated. Reverse Non-Equilibrium Molecular Dynamics (RNEMD) simulations are used to obtain the thermal conductivities in these hybrid structures and also analyze the role of the interfacial thermal resistance at the SWCNT-graphene junctions in limiting thermal transport. The highest out-of-plane (along the SWCNT axis) thermal conductivity of a hybrid structure with a CNT-graphene junction was obtained to be 158.9±1.2 W/m-K when the junction comprised of only sp2 bonds with an interpillar distance of 15 nm and a pillar height of 200 nm. The highest in-plane thermal conductivity (along the graphene layer plane) with two CNT-graphene junctions was found to be 392.2±9.9 W/m-K with junctions comprising of only sp2 bonds and an interpillar distance of 20 nm and a pillar height of 25 nm. In all cases, junctions with mixed sp2/sp3 hybridization showed higher interfacial thermal resistance than junctions with pure sp2 bonds, and the thermal interfacial resistance was found to be weakly dependent on the length of CNT and the interpillar distance. The highest interfacial thermal resistance measured across the CNT-graphene junction was 3.10×10−6 K-cm2/W when the junction comprised of mixed sp2/sp3 bonds and with 15 nm interpillar distance and 50 nm pillar height.


Author(s):  
Hua Bao ◽  
Shirui Luo ◽  
Ming Hu

Thermal transport across material interfaces is crucial for many engineering applications. For example, in microelectronics, small interfacial thermal resistance is desired to achieve efficient heat dissipation. Carbon nanotube (CNT) has extremely high thermal conductivity and can potentially serve as an efficient thermal interface material. However, heat dissipation through CNTs is limited by the large thermal resistance at the CNT-material interface. Here we have proposed a CNT-graphene junction structure to enhance the interfacial thermal transport. Non-equilibrium molecular dynamics simulations have been carried out to show that the thermal conductance can be significantly enhanced by adding a single graphene layer in between CNT and silicon. The mechanism of enhanced thermal transport is attributed to the efficient thermal transport between CNT and graphene and the good contact between graphene and silicon surface.


Sign in / Sign up

Export Citation Format

Share Document