Thermal Conductivity of Carbon Nanotube Aerogels With Different Filling Gases

2012 ◽  
Author(s):  
Scott N. Schiffres ◽  
Kyu Hun Kim ◽  
Youngseok Oh ◽  
Mohammad F. Islam ◽  
Jonathan A. Malen
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotube ◽  
Thermal Effusivity ◽  
Phonon Transport ◽  
Single Walled Carbon Nanotube ◽  
3Ω Method ◽  
Vacuum Measurement ◽  
Mechanical And Electrical Properties ◽  
Thermal Interface Resistance ◽  
Different Gases

We report on measurements of thermal conductivity in single-walled carbon nanotube (SWCNT) aerogels in vacuum, and as infiltrated by different gases. The remarkable thermal, mechanical and electrical properties of single CNTs have led to great interest in bulk carbon nanotube materials, including the CNT aerogels. Carbon nanotube aerogels are light-weight (7–8kg/m3) and porous, which means that heat will be conducted in parallel through the SWCNT matrix and the filling gas. The overall thermal conductivity of the aerogel was measured with helium, and argon filling gases, using a modified 3ω method designed to interrogate low thermal effusivity materials. Measurements of thermal conductivity at vacuum are 0.023 W/m-K and at atmospheric pressure infiltrated SWCNT aerogels have thermal conductivities in helium of 0.19 W/m-K and in argon of 0.039 W/m-K. Our vacuum measurement suggests that transport within the aerogel is limited by the thermal interface resistance between SWCNTs, rather than by phonon transport within the SWCNT itself. We have also extracted the mean distance traveled by gas molecules between collisions with SWCNT aerogel by fitting the gas contribution to thermal conductivity using a kinetic theory based model.

Synthesis and Characterization of Poly(2,5-benzimidazole) (ABPBI) Grafted Carbon Nanotubes

2009 ◽  
Vol 1240 ◽  
Author(s):  
Ji-Ye Kang ◽  
Su-Mi Eo ◽  
Loon-Seng Tan ◽  
Jong-Beom Baek
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Interfacial Adhesion ◽  
Synthesis And Characterization ◽  
Acylation Reaction ◽  
Single Walled Carbon Nanotube ◽  
Mechanical And Electrical Properties ◽  
Multi Walled Carbon Nanotube

AbstractSingle-walled carbon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT) were functionalized with 3,4-diaminobenzoic acid via “direct” Friedel-Crafts acylation reaction in PPA/P2O5 to afford ortho-diamino-functionalized SWCNT (DIF-SWCNT) and MWCNT (DIF-MWCNT). The resultant DIF-SWCNT and DIF-MWCNT showed improved solubility and dispersibility. To improve interfacial adhesion between CNT and polymer matrix, the grafting of ABPBI onto the surface of DIF-SWCNT (10 wt%) or DIF-MWCNT (10 wt%) was conducted by simple in-situ polymerization of AB monomer, 3,4-diaminobenzoic acid dihydrochloride, in PPA. The resultant ABPBI-g-MWCNT and ABPBI-g-SWCNT showed improved the mechanical and electrical properties.

Thermal and Electrical Transport Measurements of Single-Walled Carbon Nanotube Strands

2003 ◽  
Vol 788 ◽  
Author(s):  
Diana-Andra Borca-Tasciuc ◽  
Yann LeBon ◽  
Claire Nanot ◽  
Gang Chen ◽  
Theodorian Borca-Tasciuc ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Specific Heat ◽  
Electrical Transport ◽  
Published Data ◽  
Temperature Dependent ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Temperature Dependent Properties

ABSTRACTThis work reports temperature dependent thermal and electrical properties characterization of long (mm size) single-walled carbon nanotube strands. Electrical properties are measured using a 4-probe method. Thermal conductivity and specific heat capacity are determined using an AC driven, self-heating method. Normalized values of resistivity, thermal conductivity, specific heat, thermal diffusivity, and the temperature coefficient of resistance are reported. The trends observed in the temperature dependent properties are comparable with previously published data on multi-walled carbon nanotube strands measured with a similar technique.

Coupling Between Phonons and Fluid Particles in Water/Carbon Nanotube Systems

2009 ◽  
Author(s):  
A. J. H. McGaughey ◽  
J. A. Thomas ◽  
J. Turney ◽  
R. M. Iutzi
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Relaxation Times ◽  
Mean Free Path ◽  
Phonon Transport ◽  
Dynamics Simulation ◽  
Spectral Energy ◽  
Total Thermal Conductivity ◽  
Phonon Modes

We investigate thermal transport in water/carbon nanotube (CNT) composite systems using molecular dynamics simulations. Carbon-carbon interactions are modeled using the second-generation REBO potential, water-water interactions are modeled using the TIP4P potential, and carbon-water interactions are modeled using a Lennard-Jones potential. The thermal conductivities of empty and water-filled CNTs with diameters between 0.83 nm and 1.66 nm are predicted using molecular dynamics simulation and a direct application of the Fourier law. For empty CNTs, the thermal conductivity decreases with increasing CNT diameter. As the CNT length approaches 1 micron, a length-independent thermal conductivity is obtained, indicative of diffusive phonon transport. When the CNTs are filled with water, the thermal conductivity decreases compared to the empty CNTs and transitions to diffusive phonon transport at shorter lengths. To understand this behavior, we calculate the spectral energy density of the empty and water-filled CNTs and calculate the mode-specific group velocities, relaxation times, and thermal conductivity. For the empty 1.10 nm diameter CNT, we show that the acoustic phonon modes account for 65 percent of the total thermal conductivity. This behavior is attributed to their long mean-free paths. When the CNT is filled with water, interactions with the water molecules shorten the acoustic mode mean-free path and lower the overall CNT thermal conductivity.

The effect of imposed temperature difference on thermal conductivity in armchair single-walled carbon nanotube

2015 ◽  
Vol 26 (09) ◽  
pp. 1550105 ◽  
Author(s):  
Ali Mehri ◽  
Maryam Jamaati ◽  
Moslem Moradi
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotube ◽  
Heat Transport ◽  
Temperature Difference ◽  
Nonequilibrium Molecular Dynamics ◽  
Tube Length ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Brenner Potential ◽  
Umklapp Scattering

Thermal conductivity of carbon nanotubes depends on various factors. The simulation of heat transport in armchair single-walled carbon nanotube by direct nonequilibrium molecular dynamics (NEMD) method employing Tersoff–Brenner potential indicates that, thermal conductivity decreases with increase in temperature difference between two ends of the tube. Increasing the imposed temperature differential along the tube axis, leads to domination of Umklapp scattering and impacts the heat transport. The applied temperature difference does not influence the behavior of thermal conductivity vs. tube length, diameter and temperature, but changes its value.

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