Heat conduction across a solid-solid interface: Understanding nanoscale interfacial effects on thermal resistance

Balasubramanian, Ganesh; Puri, Ishwar K.

doi:10.1063/1.3607477

Cited by 78 publications

(48 citation statements)

References 25 publications

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“…One polymer can thus be thought to behave as an impurity within the other, which enhances phonon scattering just as the differences in the masses and force constants of impurity atoms within a bulk material diminish thermal transport. 31 The thermal conductivities of several unstrained polymer combinations are presented in Fig. 3, which shows that physical combinations of PANI and PA lower κ p below its value for either of the two pure polymers.…”

Section: B the Effect Of Polymer Combination On Thermal Conductivitymentioning

confidence: 99%

Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Pal

Balasubramanian

Puri

2012

The Journal of Chemical Physics

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If their thermal conductivity can be lowered, polyacetylene (PA) and polyaniline(PANI) offer examples of electrically conducting polymers that can have potential use as thermoelectrics. Thermal transport in such polymers is primarily influenced by bonded interactions and chain orientations relative to the direction of heat transfer. We employ molecular dynamics simulations to investigate two mechanisms to control the phonon thermal transport in PANI and PA, namely, (1) mechanical strain and (2) polymer combinations. The molecular configurations of PA and PANI have a significant influence on their thermal transport characteristics. The axial thermal conductivity increases when a polymer is axially stretched but decreases under transverse tension. Since the strain dependence of the thermal conductivity is related to the phonon scattering among neighboring polymer chains, this behavior is examined through Herman's orientation factor that quantifies the degree of chain alignment in a given direction. The conductivity is enhanced as adjacent chains become more aligned along the direction of heat conduction but diminishes when they are orthogonally oriented to it. Physically combining these polymers reduces the thermal conductivity, which reaches a minimum value for a 2:3 PANI/PA chain ratio. If their thermal conductivity can be lowered, polyacetylene (PA) and polyaniline (PANI) offer examples of electrically conducting polymers that can have potential use as thermoelectrics. Thermal transport in such polymers is primarily influenced by bonded interactions and chain orientations relative to the direction of heat transfer. We employ molecular dynamics simulations to investigate two mechanisms to control the phonon thermal transport in PANI and PA, namely, (1) mechanical strain and (2) polymer combinations. The molecular configurations of PA and PANI have a significant influence on their thermal transport characteristics. The axial thermal conductivity increases when a polymer is axially stretched but decreases under transverse tension. Since the strain dependence of the thermal conductivity is related to the phonon scattering among neighboring polymer chains, this behavior is examined through Herman's orientation factor that quantifies the degree of chain alignment in a given direction. The conductivity is enhanced as adjacent chains become more aligned along the direction of heat conduction but diminishes when they are orthogonally oriented to it. Physically combining these polymers reduces the thermal conductivity, which reaches a minimum value for a 2:3 PANI/PA chain ratio.

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Section: B the Effect Of Polymer Combination On Thermal Conductivitymentioning

confidence: 99%

Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Pal

Balasubramanian

Puri

2012

The Journal of Chemical Physics

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“…Thermal contact resistance also known as Kapitza resistance [28,29] is the resistance due to the presence of an interface between two dissimilar materials. This interfacial thermal resistance plays a significant role in thermal transport at nanoscale measurements [35].…”

Section: Contact Geometry (A)mentioning

confidence: 99%

Scanning thermal microscopy with heat conductive nanowire probes

et al. 2016

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(2016) 'Scanning thermal microscopy with heat conductive nanowire probes.', Ultramicroscopy., 162 . pp. 42-51.Further information on publisher's website:http://dx.doi.org/10. 1016/j.ultramic.2015.12.006 Publisher's copyright statement: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractScanning thermal microscopy (SThM), which enables measurement of thermal transport and temperature distribution in devices and materials with nanoscale resolution is rapidly becoming a key approach in resolving heat dissipation problems in modern processors and assisting development of new thermoelectric materials. In SThM, the self-heating thermal sensor contacts the sample allowing studying of the temperature distribution and heat transport in nanoscaled materials and devices. The main factors that limit the resolution and sensitivities of SThM measurements are the low efficiency of thermal coupling and the lateral dimensions of the probed area of the surface studied. The thermal conductivity of the sample plays a key role in the sensitivity of SThM measurements. During the SThM measurements of the areas with higher thermal conductivity the heat flux via SThM probe is increased compared to the areas with lower thermal conductivity. For optimal SThM measurements of interfaces between low and high thermal conductivity materials, well defined nanoscale probes with high thermal conductivity at the probe apex are required to achieve a higher quality of the probe-sample thermal contact while preserving the lateral resolution of the system.In this paper, we consider a SThM approach that can help address these complex problems by using high thermal conductivity nanowires (NW) attached to a tip apex.We propose analytical models of such NW-SThM probes and analyse the influence of the contact resistance between the SThM probe and the sample studied. The latter becomes particularly important when both tip and sample surface have high thermal conductivities.2 These models were complemented by finite element analysis simulations and experimental tests using prototype probe where a multiwall carbon nanotube (MWCNT) is exploited as an excellent example of a high thermal conductivity NW. These results elucidate critical relationships between the performance of the SThM probe on one hand and thermal conductivity, geometry of the probe and its components on the other. As such, they provide a pathway for optimizing current SThM for nanothermal studies of high thermal conductivity materials. Comparison between experimental and modelling results allows...

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“…Furthermore, recent simulation studies 28,29 have reported that the total length of the specimens affects the interface resistivity and the thermal conductivity of individual layers in SL's.…”

Section: Introductionmentioning

confidence: 99%

Thermal transport in SiGe superlattice thin films and nanowires: Effects of specimen and periodic lengths

Lin

Strachan

2013

Phys. Rev. B

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We compute the thermal conductivity of superlattice (SL) thin films and nanowires for various SL periods and total specimen lengths using non-equilibrium molecular dynamics (MD).Both types of materials exhibit similar behaviors with respect to SL period but the thermal conductivity of the thin films exhibits a significantly higher sensitivity to the specimen length.Notably, the thermal conductivity of SL thin films is smaller than those of the corresponding nanowires for specimen lengths below approximately 35 nm. These results arise from the complex dependence of the conductivities of the interfaces and the SL components on the specimen size and period. These trends and observations are explained using a simple phonon model that builds on the relationship between the cumulative thermal conductivity and the phonon wavelength.

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Heat conduction across a solid-solid interface: Understanding nanoscale interfacial effects on thermal resistance

Cited by 78 publications

References 25 publications

Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Scanning thermal microscopy with heat conductive nanowire probes

Thermal transport in SiGe superlattice thin films and nanowires: Effects of specimen and periodic lengths

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