Silica Aerogels

Malfait, Wim J.; Wernery, Jannis; Zhao, Shanyu; Brunner, Samuel; Koebel, Matthias M.

doi:10.1002/9781118801017.ch8.3

Cited by 3 publications

(2 citation statements)

References 28 publications

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“…Samuel Kistler made the first aerogel in the 1930s, a material that was later translated to the industry for thermal insulators and viscosity regulators [ 7 ]. In recent years, aerogel has seen significant advances and changes as a thermal superinsulation material.…”

Section: Introductionmentioning

confidence: 99%

An Updated Overview of Silica Aerogel-Based Nanomaterials

Niculescu,

Tudorache,

Bocioagă

et al. 2024

Nanomaterials

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Silica aerogels have gained much interest due to their unique properties, such as being the lightest solid material, having small pore sizes, high porosity, and ultralow thermal conductivity. Also, the advancements in synthesis methods have enabled the creation of silica aerogel-based composites in combination with different materials, for example, polymers, metals, and carbon-based structures. These new silica-based materials combine the properties of silica with the other materials to create a new and reinforced architecture with significantly valuable uses in different fields. Therefore, the importance of silica aerogels has been emphasized by presenting their properties, synthesis process, composites, and numerous applications, offering an updated background for further research in this interdisciplinary domain.

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Section: Introductionmentioning

confidence: 99%

An Updated Overview of Silica Aerogel-Based Nanomaterials

Niculescu,

Tudorache,

Bocioagă

et al. 2024

Nanomaterials

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“…Due to its unique microstructure, it holds 15 Guinness World Records for solid materials, including the lowest thermal conductivity (0.012-0.016 W/m•K), lowest density (0.16 mg/cm 3 ), lowest dielectric constant (< 1.003), highest acoustic impedance (106 kg/(m 2 •s)), and highest porosity (> 99.9%). [1,2] The critical electrical components and wiring of China's first Mars rover, Tianwen-1, as well as China's Zhurong rover, and the American Mars rovers, Spirit and Opportunity, all use aerogel protection to withstand temperatures as low as −100 • C. [3] The main reasons for the extremely low thermal conductivity of aerogels are twofold: the first is the high porosity of aerogels, with the porosity of silica aerogels ranging from 90% to 99%, and the volume fraction of air being as high as approximately 99.8%. [4] Heat transfer within aerogels mainly occurs through the air, and the thermal conductivity of air in standard conditions is 0.024 (W/(m•K)); the second reason is the restriction on the thermal motion of gas molecules.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study on the effective thermal conductivity of silica aerogels based on a cross-aligned and cubic pore model

Zheng 郑,

Li 李,

Cao 曹

et al. 2024

Chinese Phys. B

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Aerogel nanoporous materials possess high porosity, high specific surface area, and extremely low density due to their unique nanoscale network structure. Moreover, their effective thermal conductivity is very l1ow, making them a new type of lightweight and highly efficient nanoscale super-insulating material. However, predicting their effective thermal conductivity is challenging due to their uneven pore size distribution. To investigate the internal heat transfer mechanism of aerogel nanoporous materials, this study constructed cross-aligned and cubic pore model (CACPM) based on the actual pore arrangement of SiO2 aerogel. Based on the established cross-aligned and cubic pore model (CACPM), the effective thermal conductivity expression for aerogel was derived by simultaneously considering gas-phase heat conduction, solid-phase heat conduction, and radiative heat transfer. The derived expression was then compared with available experimental data and the Wei structure model. The results indicate that, according to the model established in this study for the derived thermal conductivity formula of silica aerogel, for powdery silica aerogel under the conditions of T=298K, a 2=0.85, D 1=90μm, ρ=128kg/m3, within the pressure range of 0-105Pa, the average deviation between the calculated values and experimental values is 10.51%. In the pressure range of 103-104Pa, the deviation between calculated values and experimental values is within 4%. Under these conditions, the model has certain reference value in engineering verification. This study also makes a certain contribution to the research of aerogel thermal conductivity heat transfer model and calculation formula.

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