Evolution of the porous volume during the aerogel-glass transformation

Woignier, Thierry; Quinson, J.F.; Pauthe, M.; Repellin-Lacroix, M.; Phalippou, J.

doi:10.1051/jp4:1992213

Cited by 4 publications

(3 citation statements)

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“…When the crystal enters a pore, it exerts pressure on the network, and this affects aerogels much the same way as during the mercury porosimetry [ 94 ]. The damage is caused by freezing and thawing the samples during this method as the method for determining the pore size distribution of mainly inorganic silica aerogels [ 95 , 96 ] or cellulosic aerogels [ 88 , 89 , 97 ] at most. Application to other bioaerogels has not been widely reported.…”

Section: Thermoporometrymentioning

confidence: 99%

A Brief Evaluation of Pore Structure Determination for Bioaerogels

Horvat

Pantić

Knez

et al. 2022

Gels

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This review discusses the most commonly employed methods for determining pore size and pore size distribution in bioaerogels. Aerogels are materials with high porosity and large surface areas. Most of their pores are in the range of mesopores, between 2 and 50 nm. They often have smaller or larger pores, which presents a significant challenge in determining the exact mean pore size and pore size distribution in such materials. The precision and actual value of the pore size are of considerable importance since pore size and pore size distribution are among the main properties of aerogels and are often directly connected with the final application of those materials. However, many recently published papers discuss or present pore size as one of the essential achievements despite the misinterpretation or the wrong assignments of pore size determination. This review will help future research and publications evaluate the pore size of aerogels more precisely and discuss it correctly. The study covers methods such as gas adsorption, from which BJH and DFT models are often used, SEM, mercury porosimetry, and thermoporometry. The methods are described, and the results obtained are discussed. The following paper shows that there is still no precise method for determining pore size distribution or mean pore size in aerogels until now. Knowing that, it is expected that this field will evolve in the future.

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Section: Thermoporometrymentioning

confidence: 99%

A Brief Evaluation of Pore Structure Determination for Bioaerogels

Horvat

Pantić

Knez

et al. 2022

Gels

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“…These results can be compared with the pore size distribution of aerogels thermally sintered and having the same density. Compression is assumed to collapse preferentially the largest pores (Pirard et al 1995), while in the case of thermal sintering, the smallest pores are first affected (Woignier et al 1992).…”

Section: Textural Evolutionmentioning

confidence: 99%

Aerogel Sintering: From Optical Glasses to Nuclear Waste Containment

Phalippou

Dieudonné

Faivre

et al. 2016

Handbook of Sol-Gel Science and Technology

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“…The evolution of the texture of silica aerogels during sintering was studied by thermoporometry for both neutral and base catalyzed materials [25]. During the densification the macroporous volume decreased and analysis of the change in the mesopore size distribution showed that collapse of the smallest mesopores was mainly responsible for the changes in pore volume transformation.…”

Section: Silica Gels and Aerogelsmentioning

confidence: 99%

Thermoporometry

Stcker¹

2002

Handbook of Porous Solids

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The texture of porous materials with pore diameters larger than about 2 nm can be characterized by a calorimetric investigation of the liquid-solid state transition of a capillary condensate saturating these materials. The method, called thermoporometry, is based on the thermodynamic conditions of the liquid-solid transformation of the capillary condensate inside the porous material [l, 21. Thermoporometry is mainly used for the determination of pore-size distribution. Upon solidification and melting of a condensate that totally saturates the porous material, the phase change takes place inside the pores and no material transport occurs. This is not the case in most adsorption experiments. The resulting freezing-point depression of the confined probe molecules and the thermal energy released or absorbed are measured as a hnction of the temperature [3]. The thermal analysis of these transformations for condensates such as water or benzene leads to the pore-size distribution through the "solidification curve". The pore shape is related to the hysteresis phenomenon observed between the solidification and melting curves, allowing a shape factor to be calculated. Thermoporometry has the following advantages:(1) it gives the actual size of the cavities instead of indicating the size of the (2) it can be performed on nonrigid materials, and (3) it can be used for the study of materials in the medium in which they are opening, applied.Thermoporometry can be used also for studying materials in which the pore diameters are in the range of approximately 2-30 nm (i.e., in the mesopore range).

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Evolution of the porous volume during the aerogel-glass transformation

Cited by 4 publications

References 0 publications

A Brief Evaluation of Pore Structure Determination for Bioaerogels

A Brief Evaluation of Pore Structure Determination for Bioaerogels

Aerogel Sintering: From Optical Glasses to Nuclear Waste Containment

Thermoporometry

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