Numerical simulations of aerogel sintering

Olivi-Tran, Nathalie; Jullien, R.

doi:10.1103/physrevb.52.258

Cited by 19 publications

(17 citation statements)

References 14 publications

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“…[1] obtained from the gel correlation length ξ g . It is worth noting that the DLCA simulated structure factors present a more pronounced maximum at q m than the experimental curves I(q), as already noticed in the literature [18,27]. There are obviously large scale inhomogeneities in actual aerogels that are not reproduced in the simulations.…”

Section: A Aerogel Structuresupporting

confidence: 52%

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Gas adsorption and desorption in silica aerogels: A theoretical study of scattering properties

et al. 2006

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We present a numerical study of the structural correlations associated with gas adsorption and desorption in silica aerogels in order to provide a theoretical interpretation of scattering experiments. Following our earlier work, we use a coarse-grained lattice-gas description and determine the nonequilibrium behavior of the adsorbed gas within a local mean-field analysis. We focus on the differences between the adsorption and desorption mechanisms and their signature in the fluid-fluid and gel-fluid structure factors as a function of temperature. At low temperature, but still in the regime where the isotherms are continuous, we find that the adsorbed fluid density, during both filling and draining, is correlated over distances that may be much larger than the gel correlation length. In particular, extended fractal correlations may occur during desorption, indicating the existence of a ramified cluster of vapor filled cavities. This also induces an important increase of the scattering intensity at small wave vectors. The similarity and differences with the scattering of fluids in other porous solids such as Vycor are discussed.

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Section: A Aerogel Structuresupporting

confidence: 52%

“…Moreover, as emphasized in Refs. [18,27], there are some significant details that are neglected in the DLCA model, such as the rotational diffusion of the aggregates, their polydispersity and irregular form, and all kinds of possible restructurating effects.…”

Section: A Aerogel Structurementioning

confidence: 99%

Gas adsorption and desorption in silica aerogels: A theoretical study of scattering properties

et al. 2006

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“…The advantage of this model is that the changes of different scales of fractal clusters during the sintering process come out naturally and can be quantitatively studied on a statistical basis. Similar to the "dressing" and "contraction" method proposed by OliviTran and Jullien (39), this model can trace the topological evolution of dendritic structures during the sintering process without relying on detailed information on material properties (such as surface tension and viscosity). This is desirable as these properties are not well established for nanometer-sized particles.…”

Section: Local Group Merge Sintering Model (Lgmsm)mentioning

confidence: 96%

Computer Simulation of the Aggregation and Sintering Restructuring of Fractal-like Clusters Containing Limited Numbers of Primary Particles

Yang

Biswas

1999

Journal of Colloid and Interface Science

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“…Huang et al investigated the structural changes of silica aerogels in the 9501200 ℃ temperature range. Their results showed that the process consists of three steps [14,15].…”

Section: Introduction mentioning

confidence: 99%

A study of morphological properties of SiO2 aerogels obtained at different temperatures

Liao

Gao

et al. 2018

J Adv Ceram

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In this paper, temperature dependence of nanoporous framework evolution process and variety of pore properties (pore volume, specific surface area (BET), and pore size) of SiO 2 aerogels were characterized by FTIR, XPS, XRD, SEM, TEM, BET, BJH, etc. Results show that SiO 2 aerogels treated at different temperatures all possess amorphous structure. With the increase of treated temperatures, BET values of SiO 2 aerogels increase initially and then decrease, and it reaches the maximum value of 882.81 m 2 /g when treated at 600 ℃ for 2 h due to the addition of the nanopores and shrinkage skeleton of SiO 2 aerogels. Higher temperatures may result in a framework transformation and particle growth; both factors could reduce the BET values of the aerogels. Nanoporous skeleton of SiO 2 aerogels at room temperatures is composed of tetrahedron with a pore size of about 22.28 nm. Higher treated temperatures result in an increase of octahedron amount in nanoporous framework and a decrease of pore size. When treated at 1000 ℃, an approximate dense SiO 2 bulk via the framework collapse and particle growth is obtained. These varieties are derived from the formed extra bonds of Si-O-Si, higher local stress, and liquid phase between particles during heat treatment process.

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Numerical simulations of aerogel sintering

Cited by 19 publications

References 14 publications

Gas adsorption and desorption in silica aerogels: A theoretical study of scattering properties

Gas adsorption and desorption in silica aerogels: A theoretical study of scattering properties

Computer Simulation of the Aggregation and Sintering Restructuring of Fractal-like Clusters Containing Limited Numbers of Primary Particles

A study of morphological properties of SiO2 aerogels obtained at different temperatures

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