Thermal Conductivity Measurement for Carbon-Nanotube Suspensions with 3ω Method

The stable and homogeneneous aqueous suspension of carbon nanotubes was prepared in this study. The stability of the nanofluids was improved greatly due to the use of a new dispersant, humic acid. The thermal conductivity of the aqueous suspension was measured with the 3ω method. The experimental results showed that the thermal conductivity of the suspensions increases with the temperature and also is nearly proportional to the loading of the nanoparticles. The thermal conductivity enhancement of single-walled carbon nanotubes (SWNTs) suspensions is better than that of the multi-walled carbon nanotubes (MWNTs) suspensions. Especially for a volume fraction of 0.3846% SWNTs, the thermal conductivity is enhanced by 40.5%. Furthermore, the results at 30°C match well with Jang and Choi’s model.

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Mechanistic Investigations of Viscosity and Thermal Conductivity Enhancement in Multi-Walled Carbon Nanotubes-Propylene Glycol Nanofluids

Nanoscience and Nanotechnology Letters ◽

10.1166/nnl.2013.1673 ◽

2013 ◽

Vol 5 (10) ◽

pp. 1125-1129 ◽

Cited By ~ 9

Author(s):

A. Helen Mary ◽

K. S. Suganthi ◽

K. S. Rajan

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Propylene Glycol ◽

Thermal Conductivity Enhancement ◽

Conductivity Enhancement ◽

Multi Walled Carbon Nanotubes ◽

Mechanistic Investigations ◽

Walled Carbon Nanotubes

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Thermophysical Properties of IoNanofluids Composed of 1-ethyl-3-methylimidazolium Thiocyanate and Carboxyl-functionalized Long Multi-walled Carbon Nanotubes

Fluids ◽

10.3390/fluids5040214 ◽

2020 ◽

Vol 5 (4) ◽

pp. 214

Author(s):

Bertrand Jóźwiak ◽

Justyna Dziadosz ◽

Adrian Golba ◽

Krzysztof Cwynar ◽

Grzegorz Dzido ◽

...

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Carboxylic Group ◽

Conductivity Enhancement ◽

Multi Walled Carbon Nanotubes ◽

Vibrating Tube Densimeter ◽

Carbon Based Nanomaterials ◽

Walled Carbon Nanotubes ◽

Rotary Viscometer

The concept of IoNanofluids (INFs) as the stable dispersions of nanoparticles in ionic liquids was proposed in 2009 by Nieto de Castro’s group. INFs characterize exciting properties such as improved thermal conductivity, non-volatility, and non-flammability. This work is a continuation of our studies on the morphology and physicochemistry of carbon-based nanomaterials affecting thermal conductivity, viscosity, and density of INFs. We focus on the characterization of dispersions composed of long carboxylic group-functionalized multi-walled carbon nanotubes and 1-ethyl-3-methylimidazolium thiocyanate. The thermal conductivity of INFs was measured using KD2 Pro Thermal Properties Analyzer (Decagon Devices Inc., Pullman, WA, USA). The viscosity was investigated using rotary viscometer LV DV-II+Pro (Brookfield Engineering, Middleboro, MA, USA). The density of INFs was measured using a vibrating tube densimeter Anton Paar DMA 5000 (Graz, Austria). The maximum thermal conductivity enhancement of 22% was observed for INF composed of 1 wt% long carboxylic group-functionalized multi-walled carbon nanotubes.

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Thermophysical Properties of Nanofluids Composed of Ethylene Glycol and Long Multi-Walled Carbon Nanotubes

Fluids ◽

10.3390/fluids5040241 ◽

2020 ◽

Vol 5 (4) ◽

pp. 241

Author(s):

Karolina Brzóska ◽

Bertrand Jóźwiak ◽

Adrian Golba ◽

Marzena Dzida ◽

Sławomir Boncel

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Ethylene Glycol ◽

Chemical Vapor ◽

Step Method ◽

Mwcnt Content ◽

Multi Walled Carbon Nanotubes ◽

The Stability ◽

Walled Carbon Nanotubes ◽

Rotary Viscometer

In this work, thermal conductivity, viscosity, isobaric heat capacity, and density of stable carbon-based nanofluids are presented. The nanofluids under study are composed of 1,2-ethanediol (ethylene glycol, EG) and long multi-walled carbon nanotubes (MWCNTs), so-called ‘in-house 16h’ (synthesized in our laboratory via catalytic chemical vapor deposition during 16 h with a diameter of 60–80 nm and length of 770 μm). Poly(N-vinylpyrrolidone) (PVP) was used to increase the stability of nanofluids. The nanofluids were prepared via an ultrasonication-assisted, three-step method while their key thermophysical characteristics were obtained using the hot-wire technique and rotary viscometer. As a result, the addition of MWCNTs significantly improved the thermal conductivity of nanofluids by 31.5% for the highest 1.0 wt% (0.498 vol%) long MWCNT content, leaving the Newtonian character of the nanofluids practically intact.

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Water Based Multiwalled Carbon Nanotube Nanofluids With Optimized Thermal Conductivity

ASME 2009 7th International Conference on Nanochannels, Microchannels and Minichannels ◽

10.1115/icnmm2009-82055 ◽

2009 ◽

Author(s):

Li Fei Chen ◽

Huaqing Xie ◽

Wei Yu ◽

Yang Li

Keyword(s):

Thermal Conductivity ◽

Ball Milling ◽

Volume Fraction ◽

Free Water ◽

Strong Acid ◽

Multiwalled Carbon ◽

Conductivity Enhancement ◽

Water Based ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

We report a method to prepare surfactant-free water based nanofluids containing multi-walled carbon nanotubes (CNTs). The as prepared CNTs with hard dispersibility, after being cut by mechanical ball-milling approach following strong acid treatment, can be directly dispersed into water. The thermal conductivity of the nanofluids is optimized by controlling the CNT length and straightness. It is realized by changed the ball-milling times. The thermal conductivity enhancement of water based CNT nanofluids with volume fraction of 1% attains 29.5% by controlling the CNT length and straightness when the temperature is 63.9°C.

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Enhanced Thermal Conductivity of Nanofluid by Synergistic Effect of Multi-Walled Carbon Nanotubes and Fe2O3 Nanoparticles

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.548-549.118 ◽

2014 ◽

Vol 548-549 ◽

pp. 118-123 ◽

Cited By ~ 14

Author(s):

Li Fei Chen ◽

Min Cheng ◽

De Jun Yang ◽

Lei Yang

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Synergistic Effect ◽

Interfacial Adhesion ◽

Conductivity Enhancement ◽

Hybrid Fillers ◽

Water Based ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

Enhanced Thermal Conductivity

This study investigates the synergistic effect of combining multi-walled carbon nanotubes (MWNTs) and Fe2O3nanoparticles on thermal conductivity of nanofluid. Results show that low percentage hybrid fillers loading improve thermal conductivity of water based nanofluid, due to the good dispersion and interfacial adhesion, which is confirmed by scanning electron microscope. Furthermore, the hybrid fillers provide synergistic effect on heat conductive networks. The thermal conductivity enhancement of water based nanofluid containing 0.05 wt % MWNTs and 0.02 wt % Fe2O3nanoparticles is 27.75%, which is higher than that of nanofluid containing 0.2 wt % single MWNTs or Fe2O3nanoparticles.

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Stabilizing effect of methylcellulose on the dispersion of multi-walled carbon nanotubes in cementitious composites

Nanotechnology Reviews ◽

10.1515/ntrev-2020-0009 ◽

2020 ◽

Vol 9 (1) ◽

pp. 93-104

Author(s):

Mingrui Du ◽

Yuan Gao ◽

Guansheng Han ◽

Luan Li ◽

Hongwen Jing

Keyword(s):

Carbon Nanotubes ◽

Pore Solution ◽

Cementitious Materials ◽

High Ionic Strength ◽

Cementitious Composites ◽

Uniform Distributions ◽

Stabilizing Effect ◽

Multi Walled Carbon Nanotubes ◽

The Stability ◽

Walled Carbon Nanotubes

AbstractMulti-walled carbon nanotubes (MWCNTs) have been added in the plain cementitious materials to manufacture composites with the higher mechanical properties and smart behavior. The uniform distributions of MWCNTs is critical to obtain the desired enhancing effect, which, however, is challenged by the high ionic strength of the cement pore solution. Here, the effects of methylcellulose (MC) on stabilizing the dispersion of MWCNTs in the simulated cement pore solution and the viscosity of MWCNT suspensions werestudied. Further observations on the distributions of MWCNTs in the ternary cementitious composites were conducted. The results showed that MC forms a membranous envelope surrounding MWCNTs, which inhibits the adsorption of cations and maintains the steric repulsion between MWCNTs; thus, the stability of MWCNT dispersion in cement-based composites is improved. MC can also work as a viscosity adjuster that retards the Brownian mobility of MWCNTs, reducing their re-agglomerate within a period. MC with an addition ratio of 0.018 wt.% is suggested to achieve the optimum dispersion stabilizing effect. The findings here provide a way for stabilizing the other dispersed nano-additives in the cementitious composites.

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