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Titolo: SMALLANGLE NEUTRONSCATTERING OF AEROGELS  SIMULATIONS AND EXPERIMENTS
Autore: HASMY A; FORET M; ANGLARET E; PELOUS J; VACHER R; JULLIEN R;
 Indirizzi:
 UNIV MONTPELLIER 2,SCI MAT VITREUX LAB,CNRS,UA 1119,PL EUGENE BATAILLON F34095 MONTPELLIER 5 FRANCE
 Titolo Testata:
 Journal of noncrystalline solids
,
volume: 186,
anno: 1995,
pagine: 118  130
 SICI:
 00223093(1995)186:<118:SNOAS>2.0.ZU;2M
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 CLUSTERCLUSTER AGGREGATION; DIFFUSIONLIMITED AGGREGATION; SILICA AEROGELS; 3 DIMENSIONS; MODEL; SIZE; SPHERES; GELS;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Science Citation Index Expanded
 Citazioni:
 36
 Recensione:
 Indirizzi per estratti:



 Citazione:
 A. Hasmy et al., "SMALLANGLE NEUTRONSCATTERING OF AEROGELS  SIMULATIONS AND EXPERIMENTS", Journal of noncrystalline solids, 186, 1995, pp. 118130
Abstract
Numerical simulation of silica aerogels was performed using diffusionlimited clustercluster aggregation of spheres inside a cubic box (with periodic boundary conditions). The volume fraction, c, was taken tobe sufficiently; large to obtain a gel structure at the end of the process. In the case of monodisperse spheres, the wavevectordependent scattered intensity, I(q), was calculated from the product of the formfactor, P(q). of a sphere by the structure factor, S(q). which is related to the Fourier transform of g(r)1, where g(r) is the pair correlation function betwteen spheres centers. The structure factor, S(q), exhibits largeq damped oscillations characteristics of the shortrange(intraaggregate) correlations between spheres. These oscillations influence the I(q) curve in the region of q between the fractal regime and the Porod regime and quantitative comparisons were made with experiments on colloidal aerogels. At small values of q. S(q) goes through amaximum characteristic of largerange (interaggregate) correlations. Quantitative fits of the maximum in the experimental I(q) curves of basecatalyzed aerogels are presented. In the case of polydisperse spheres, I(q) was directly calculated from a single aggregate simulation. increasing polydispersity shifts the location of the crossover between the fractal and Pored regimes towards lower values of q.
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Documento generato il 02/12/20 alle ore 18:32:37