Tunable Thermal Conductivity of TiO2 Films of Close-Packed Nanoparticles

We report on the ultra-low thermal conductivity of a series of convectively assembled, anisotropic titania (TiO2) nanoparticle films. The TiO2 films are fabricated on aluminum coated glass substrates by flow coating a suspension of ellipsoidal colloidal nanoparticles, resulting in structured films with tailored order. Time domain thermoreflectance is used to measure the thermal conductivity of the TiO2 films. The thermal conductivities of these nanoparticle films are dependent on nanoparticle orientational order and films with more randomly oriented particles exhibit thermal conductivities less than the amorphous limit.

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Experimental Investigation on the Thermal Insulation Properties of Eic-Cellulose

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.554.322 ◽

2014 ◽

Vol 554 ◽

pp. 322-326 ◽

Cited By ~ 1

Author(s):

Wuryanti Sri ◽

Suhardjo Poertadji ◽

Bambang Soegijono ◽

Nasution Henry

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Experimental Investigation ◽

Thermal Insulation ◽

Cellulose Fibers ◽

Extraction Process ◽

Thermal Capacity ◽

Insulation Material ◽

Low Thermal Conductivity ◽

Thermal Conductivities

The material with low thermal conductivity means it has a high insulating capability for reducing heat transfer. One of materials for insulation is cellulose. This study presents a insulation material of cellulose made from reeds imperata cylindrical type with the extraction process. The extraction of cellulose fibers to form a sheet by adding 3.5% Na-CMC (Sodium Cellulose Carboksil Metyl). The process of forming the sheet uses blender for 30 minutes, 45 minutes, and 60 minutes. Furthermore, each mixture are put into the oven with temperature of 40°C for 36 hours. There are three parameters will be investigated, i.e. thermal conductivity, density and thermal capacity. The results showed that the lowest and the highest of thermal conductivities were 0.22 W/m K and a maximum 0.36 W/m K, respectively.

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Ultra-low thermal conductivity of ellipsoidal TiO2 nanoparticle films

Applied Physics Letters ◽

10.1063/1.3644987 ◽

2011 ◽

Vol 99 (13) ◽

pp. 133106 ◽

Cited By ~ 17

Author(s):

Patrick E. Hopkins ◽

Manish Mittal ◽

Leslie M. Phinney ◽

Anne M. Grillet ◽

Eric M. Furst

Keyword(s):

Thermal Conductivity ◽

Tio2 Nanoparticle ◽

Low Thermal Conductivity ◽

Nanoparticle Films

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Numerical Study on the Interaction of Transverse and Longitudinal Roughness on Elastohydrodynamic Lubrication Contact Surfaces With Different Thermal Conductivities and Elastic Moduli

Journal of Tribology ◽

10.1115/1.4049259 ◽

2020 ◽

Vol 143 (9) ◽

Author(s):

Motohiro Kaneta ◽

Kenji Matsuda ◽

Jing Wang ◽

Jinlei Cui ◽

Peiran Yang ◽

...

Keyword(s):

Thermal Conductivity ◽

Finite Length ◽

Elastic Moduli ◽

Elastohydrodynamic Lubrication ◽

High Thermal Conductivity ◽

Low Thermal Conductivity ◽

Longitudinal Roughness ◽

Transverse Roughness ◽

Contact Surfaces ◽

Thermal Conductivities

Abstract The interaction and surface features between point contact surfaces composed of longitudinal roughness with infinite or finite length and transverse roughness were discussed based on a transient non-Newtonian thermal elastohydrodynamic lubrication (EHL) model. Each surface shape is greatly affected by the difference in elastic moduli, thermal conductivities, and velocities of both contact surfaces. There is a large difference in pressure behavior when the transverse roughness is in contact with the longitudinal roughness with finite length and when it is in contact with the longitudinal roughness with infinite length. In the contact between surfaces with infinitely long longitudinal and transverse roughness, the friction coefficient is lower when the surface with longitudinal roughness has a low thermal conductivity than when it has a high thermal conductivity. Furthermore, the pressure fluctuation is larger when the transverse roughness surface has a high thermal conductivity than when it has a low thermal conductivity.

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Structure and Thermoelectric Properties of New Quaternary Tin and Lead Bismuth Selenides, K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1+xSn5-xBi11+xSe22

MRS Proceedings ◽

10.1557/proc-626-z8.4 ◽

2000 ◽

Vol 626 ◽

Author(s):

Antje Mrotzek ◽

Kyoung-Shin Choi ◽

Duck-Young Chung ◽

Melissa A. Lane ◽

John R. Ireland ◽

...

Keyword(s):

Thermal Conductivity ◽

Single Crystal ◽

Thermoelectric Properties ◽

Three Dimensional ◽

Structure Type ◽

Narrow Gap ◽

Low Thermal Conductivity ◽

Seebeck Coefficients ◽

Metal Atoms ◽

Anionic Framework

ABSTRACTWe present the structure and thermoelectric properties of the new quaternary selenides K1+xM4–2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22. The compounds K1+xM4-2xBi7+xSe15 (M= Sn, Pb) crystallize isostructural to A1+xPb4-2xSb7+xSe15 with A = K, Rb, while K1-xSn5-xBi11+xSe22 reveals a new structure type. In both structure types fragments of the Bi2Te3-type and the NaCl-type are connected to a three-dimensional anionic framework with K+ ions filled tunnels. The two structures vary by the size of the NaCl-type rods and are closely related to β-K2Bi8Se13 and K2.5Bi8.5Se14. The thermoelectric properties of K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22 were explored on single crystal and ingot samples. These compounds are narrow gap semiconductors and show n-type behavior with moderate Seebeck coefficients. They have very low thermal conductivity due to an extensive disorder of the metal atoms and possible “rattling” K+ ions.

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Extremely Low Thermal Conductivity of Graphene Nanoplatelets Using Nanoparticle Decoration

ES Energy & Environments ◽

10.30919/esee8c139 ◽

2018 ◽

Cited By ~ 6

Author(s):

Lin Qiu ◽

◽

Pu Guo ◽

Hanying Zou ◽

Yanhui Feng ◽

...

Keyword(s):

Thermal Conductivity ◽

Graphene Nanoplatelets ◽

Low Thermal Conductivity

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A Novel Poly(Ionic Liquid) as the Thermal Insulating Material

Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) ◽

10.2174/2405520413666200207114107 ◽

2020 ◽

Vol 13 (3) ◽

pp. 241-247

Author(s):

Wenxin Wei ◽

Guifeng Ma ◽

Hongtao Wang ◽

Jun Li

Keyword(s):

Thermal Conductivity ◽

Ionic Liquid ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Flame Resistance ◽

Insulating Material ◽

Low Thermal Conductivity ◽

Thermal Insulating ◽

Poly Ionic Liquid

Objective: A new poly(ionic liquid)(PIL), poly(p-vinylbenzyltriphenylphosphine hexafluorophosphate) (P[VBTPP][PF6]), was synthesized by quaternization, anion exchange reaction, and free radical polymerization. Then a series of the PIL were synthesized at different conditions. Methods: The specific heat capacity, glass-transition temperature and melting temperature of the synthesized PILs were measured by differential scanning calorimeter. The thermal conductivities of the PILs were measured by the laser flash analysis method. Results: Results showed that, under optimized synthesis conditions, P[VBTPP][PF6] as the thermal insulator had a high glass-transition temperature of 210.1°C, high melting point of 421.6°C, and a low thermal conductivity of 0.0920 W m-1 K-1 at 40.0°C (it was 0.105 W m-1 K-1 even at 180.0°C). The foamed sample exhibited much low thermal conductivity λ=0.0340 W m-1 K-1 at room temperature, which was comparable to a commercial polyurethane thermal insulating material although the latter had a much lower density. Conclusion: In addition, mixing the P[VBTPP][PF6] sample into polypropylene could obviously increase the Oxygen Index, revealing its efficient flame resistance. Therefore, P[VBTPP][PF6] is a potential thermal insulating material.

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