Thermal conductivity from hierarchical heat sinks using carbon nanotubes and graphene nanosheets

Nanoscale ◽  
2015 ◽  
Vol 7 (44) ◽  
pp. 18663-18670 ◽  
Author(s):  
Chien-Te Hsieh ◽  
Cheng-En Lee ◽  
Yu-Fu Chen ◽  
Jeng-Kuei Chang ◽  
Hsi-sheng Teng
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Thermal Management ◽  
Graphene Nanosheets ◽  
Consumer Electronics ◽  
Experimental Results ◽  
Heat Sinks ◽  
Empirical Equations ◽  
The Relationship

The relationship between thermal conductivity (k) and electrical conductivity (ε) values was well described by two empirical equations. The experimental results were obtained within the 323–373 K range, suitably complementing the thermal management of chips for consumer electronics.

scholarly journals High-Performance Thermal Management Nanocomposites: Silver Functionalized Graphene Nanosheets and Multiwalled Carbon Nanotube

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 398 ◽  
Author(s):  
Yongcun Zhou ◽  
Xiao Zhuang ◽  
Feixiang Wu ◽  
Feng Liu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotube ◽  
Polymer Composites ◽  
Thermal Management ◽  
High Performance ◽  
Graphene Nanosheets ◽  
Multiwalled Carbon Nanotube ◽  
Processing Unit ◽  
Functionalized Graphene ◽  
Multiwalled Carbon

Polymer composites with high thermal conductivity have a great potential for applications in modern electronics due to their low cost, easy process, and stable physical and chemical properties. Nevertheless, most polymer composites commonly possess unsatisfactory thermal conductivity, primarily because of the high interfacial thermal resistance between inorganic fillers. Herein, we developed a novel method through silver functionalized graphene nanosheets (GNS) and multiwalled carbon nanotube (MWCNT) composites with excellent thermal properties to meet the requirements of thermal management. The effects of composites on interfacial structure and properties of the composites were identified, and the microstructures and properties of the composites were studied as a function of the volume fraction of fillers. An ultrahigh thermal conductivity of 12.3 W/mK for polymer matrix composites was obtained, which is an approximate enhancement of 69.1 times compared to the polyvinyl alcohol (PVA) matrix. Moreover, these composites showed more competitive thermal conductivities compared to untreated fillers/PVA composites applied to the desktop central processing unit, making these composites a high-performance alternative to be used for thermal management.

scholarly journals Investigation of thermal conductivity of single-wall carbon nanotubes

2011 ◽  
Vol 15 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Mahmoud Jafari ◽  
Majid Vaezzadeh ◽  
Momhamad Mansouri ◽  
Abazar Hajnorouzi
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Theoretical Model ◽  
Potential Energy ◽  
Experimental Results ◽  
Single Wall Carbon Nanotubes ◽  
Lattice Vibrations ◽  
Single Wall Carbon ◽  
Thermal Potential ◽  
Conductivity Behavior

In this paper, the thermal conductivity of Single-wall carbon nanotubes (SWCNTs) is determined by lattice vibrations (phonons) and free elections. The thermal conductivity of SWCNTs is modeled up to 8-300 K and the observed deviations in K-T figures of SWCNTs are explained in terms of phonon vibrations models. An suitable theoretical model is shown for thermal conductivity behavior with respect to temperature and is generalized for experimental results. This model enables us to calculate thermal conductivity SWNTs and Thermal Potential Energy (TPE).

Incorporating Ag Nanowires into Graphene Nanosheets for Enhanced Thermal Conductivity: Implications for Thermal Management

2020 ◽  
Vol 3 (6) ◽  
pp. 6061-6070
Author(s):  
Ya Li ◽  
Xu Li ◽  
Md Mofasserul Alam ◽  
Dongbo Yu ◽  
Jibin Miao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
Graphene Nanosheets ◽  
Ag Nanowires ◽  
Enhanced Thermal Conductivity

A Comparison of the Effect of Hydroxyl Modified Carbon Nanotubes and Graphenes on the Electrical and Mechanical Properties of Their Polyurethane Composites

2012 ◽  
Vol 622-623 ◽  
pp. 781-786
Author(s):  
Sarojini Swain ◽  
Subhendu Bhattacharya ◽  
Ram Avatar Sharma ◽  
Lokesh Chaudhari
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Filler Content ◽  
Graphene Nanosheets ◽  
Three Dimensional ◽  
Conduction System ◽  
Multi Walled Carbon Nanotubes ◽  
Electrical Conduction Mechanisms ◽  
Modified Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Hydroxyl modified multi-walled carbon nanotubes (OH-MWCNT)/ polyurethane (PU) and graphene nanosheets (GNS)/PU composites were prepared by dispersing the OH-MWCNT and GNS at different wt % in to the PU matrix. It was found that the electrical percolation threshold of the GNS/PU composite is much higher compared to that of OH-MWCNT/PU and also the electrical conductivity of the OH-MWCNT/PU composite is higher than the GNS/PU composite in the same level of filler content. This may be due to the two composites having different electrical conduction mechanisms: The OH-MWCNT/PU composite represents a three dimensional conduction system while, the GNS/PU composite represents a two dimensional conduction system. The improvement in the electrical conductivity with the incorporation of GNS as a filler in the composite is far lower than what theoretically expected. It is also observed that the tensile strength of the OH-MWCNT/PU composite is higher compared to the GNS/PU in the same level filler content.

Thermal Property Measurements of Nanotubes, Nanowires, and Nanobelts

2002 ◽  
Author(s):  
Deyu Li ◽  
Arun Majumdar ◽  
Wanyoung Jang ◽  
Zhen Yao ◽  
Philip Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Boundary Scattering ◽  
Theoretical Expectation ◽  
Low Dimensions ◽  
Vlsi Interconnects ◽  
Nanoelectronic Devices ◽  
Ideal Candidate ◽  
Structure Boundary

As materials are confined to low dimensions with a size comparable to the scattering mean free paths, the thermal conductivity is often reduced due to increased boundary scattering. The reduced thermal conductivity is desirable in some applications such as thermoelectric cooling, but is often unwanted for others especially for nanoelectronic devices. An exception of this scaling trend is carbon nanotubes (CNTs). Due to the unique crystalline structure, boundary scattering is nearly absent in CNTs, giving rise to super high thermal and electrical conductivity that makes the CNT an ideal candidate for replacing Cu in future VLSI interconnects. The potential electronic applications have inspired several groups to employ a variety of techniques for measuring the Seebeck coefficient [1], specific heat [2–3], and thermal conductivity [4] of CNT bundles and mats. Estimated thermal conductivity from these measurements is significantly reduced by numerous tube-tube junctions in the sample and is much lower than the theoretical expectation [5–7].

Thermally Conductive Plastics for Enhanced Thermal Management

2015 ◽  
Vol 2015 (1) ◽  
pp. 000530-000535
Author(s):  
Chandrashekar Raman
Keyword(s):  
Thermal Conductivity ◽  
Natural Convection ◽  
Thermal Management ◽  
Electronic Devices ◽  
Heat Sinks ◽  
Significant Challenge ◽  
Design Engineers ◽  
Thermally Conductive ◽  
New Material ◽  
Conductive Plastics

Electronic devices continue to shrink while continuing to offer increasing functionality. This trend poses a significant challenge to design engineers who need to adequately address the increasing thermal management requirements of these devices on a shrinking footprint. Thermally conductive plastics have been gaining attention as an innovative new material option to address this challenge. While plastics are typically poor conductors of heat, it is possible to increase the thermal conductivity with the use of certain additives. Unique ceramic additives like boron nitride offer the added advantage of enabling thermally conductive plastic formulations that are also electrically insulating. The replacement of aluminum heat sinks in free (natural) convection environments with thermally conductive plastics is discussed in this paper. The results show it may indeed be possible to replace aluminum with thermally conductive plastic heat sinks in convection limited environments, and if judicious redesign of the plastic heat sink is incorporated, an improved thermal management solution can be realized. Additionally, the benefits of enhancing existing plastic housings to enable an improved thermal management solution are discussed. The results also show that modest enhancements to the thermal conductivity of existing plastic housings can yield significant improvements to the overall thermal management solution as well.

Improving Electrical Conductivity and Thermal Properties of Polymers by the Addition of Carbon Nanotubes as Fillers

MRS Bulletin ◽  
2007 ◽  
Vol 32 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Karen I. Winey ◽  
Takashi Kashiwagi ◽  
Minfang Mu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Polymer Composites ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Aspect Ratios ◽  
Polymer Properties ◽  
The Matrix ◽  
Conductivity Of Nanotubes

AbstractThe remarkable electrical and thermal conductivities of isolated carbon nanotubes have spurred worldwide interest in using nanotubes to enhance polymer properties. Electrical conductivity in nanotube/polymer composites is well described by percolation, where the presence of an interconnected nanotube network corresponds to a dramatic increase in electrical conductivity ranging from 10−5 S/cm to 1 S/cm. Given the high aspect ratios and small diameters of carbon nanotubes, percolation thresholds are often reported below 1 wt% although nanotube dispersion and alignment strongly influence this value. Increases in thermal conductivity are modest (∼3 times) because the inter facial thermal re sis tance between nanotubes is considerable and the thermal conductivity of nanotubes is only 104 greater than the polymer, which forces the matrix to contribute more toward the composite thermal conductivity, as compared to the contrast in electrical conductivity, >1014. The nanotube network is also valuable for improving flame-retardant efficiency by producing a protective nanotube residue. In this ar ticle, we highlight published research results that elucidate fundamental structure–property relationships pertaining to electrical, thermal, and/or flammability properties in numerous nanotube-containing polymer composites, so that specific applications can be targeted for future commercial success.

Thermal Transport Properties of Ag-Based Nanocomposites Containing MWCNTs

2012 ◽  
Vol 1404 ◽  
Author(s):  
M. Inoue ◽  
Y. Hayashi ◽  
H. Takizawa
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Electronic Contribution ◽  
Nanocomposite Powder ◽  
Multi Walled Carbon Nanotubes ◽  
Experimental Values ◽  
Walled Carbon Nanotubes ◽  
Percolation Network

ABSTRACTVariation in thermal conductivity of Ag-based composites by introduction of multi-walled carbon nanotubes (MWCNTs) was investigated. The Ag/MWCNT nanocomposite powder was successfully prepared when appropriate surfactants were used via a sonoprocess. The nanocomposite powder was subsequently cured at 280-300 ºC in air. After curing, the thermal conductivity of the nanocomposites was compared with the electronic contribution to thermal conductivity that was estimated from experimental values of the electrical conductivity. The thermal conductivity of Ag/MWCNT nanocomposites was much higher than the electronic contribution. Therefore, the increase in thermal conductivity of the Ag-based nanocomposites is attributed to phonon transfer along the percolation network of MWCNTs.

The Thermal Expansion Behaviors of Cu-SiCp Composites

2013 ◽  
Vol 795 ◽  
pp. 237-240
Author(s):  
K. Azmi ◽  
M.N. Derman ◽  
Mohd Mustafa Al Bakri Abdullah
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Thermal Expansion ◽  
Thermal Management ◽  
Thermophysical Properties ◽  
Copper Matrix ◽  
Experimental Results ◽  
High Thermal Conductivity ◽  
Coating Process ◽  
Electroless Coating

The demand for advanced thermal management materials such as silicon carbide reinforced copper matrix (Cu-SiCp) composites is increasing due to their high thermal conductivity and low CTE properties. However, the weak bonding between the copper matrix and the SiCp reinforcement degrades the thermophysical properties of the composites. In order to improve the bonding between the two constituents, the SiCp were copper coated (Cu-Coated) via electroless coating process. Based on the experimental results, the CTE values of the Cu-Coated Cu-SiCp composites were found significantly lower than those of the non-Coated Cu-SiCp composites. The CTEs of the Cu-Coated Cu-SiCp composites were in agreement with Kernels model which accounts for both the shear and isostatic stresses developed in the component phases.

Thermal Conductivity of Carbon Nanotubes With Defects

2011 ◽  
Author(s):  
Haibin Chen ◽  
Alan J. H. McGaughey
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Thermal Management ◽  
Direct Application ◽  
Dynamics Simulation ◽  
Fourier Law ◽  
Pristine Cnts ◽  
Thermal Conductivities

The high thermal conductivities of carbon nanotubes (CNTs) measured experimentally and predicted from theory suggest that they are good candidates for next-generation thermal management materials. The quantities of CNTs needed in applications preclude the use of pristine products. Limited work, however, has been done to study thermal transport in CNTs with defects. In this paper, the thermal conductivities of pristine CNTs and CNTs with various defect types (adatoms, single vacancies, double vacancies, and Stone-Wales) are systematically predicted using molecular dynamics simulation and a direct application of the Fourier law. We investigate the correlation between the thermal conductivity and defect energy.

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