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Titolo:
A LOW-FREQUENCY RAMAN-STUDY OF FRACTONS IN PARTIALLY DENSIFIED SILICAAEROGELS
Autore:
ANGLARET E; BEURROIES I; DUFFOURS L; LEVELUT C; FORET M; DELORD P; WOIGNIER T; PHALIPPOU J; PELOUS J;
Indirizzi:
UNIV MONTPELLIER 2,DYNAM PHASES CONDENSEES GRP MONTPELLIER FRANCE UNIV MONTPELLIER 2,LAB VERRES MONTPELLIER FRANCE
Titolo Testata:
Journal of non-crystalline solids
fascicolo: 1, volume: 225, anno: 1998,
pagine: 248 - 253
SICI:
0022-3093(1998)225:1<248:ALROFI>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANGLE NEUTRON-SCATTERING; SIMULATIONS;
Keywords:
RAMAN STUDY; AEROGELS; HYDROSTATIC PRESSURE; DENSIFICATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
17
Recensione:
Indirizzi per estratti:
Citazione:
E. Anglaret et al., "A LOW-FREQUENCY RAMAN-STUDY OF FRACTONS IN PARTIALLY DENSIFIED SILICAAEROGELS", Journal of non-crystalline solids, 225(1), 1998, pp. 248-253

Abstract

We report on a low-frequency Raman scattering study of base-catalyzedsilica aerogels (BCSA) and partially densified BCSA prepared by heat treatment (HT), hydrostatic pressure (HP) and uniaxial pressure (UP). Low-frequency Raman susceptibility scales with frequency, chi(omega) similar to omega(-phi) within a large range of frequencies whose extentdecreases with densification. Changes in the spectra are correlated with densification-induced changes in structure and connectivity of BCSA. phi is a constant independent of density for all as-prepared samples, in agreement with their mutual self-similarity. phi also remains essentially constant for HT samples while it decreases for HP and UP samples. phi values are discussed in terms of fractal and spectral dimensions of the samples in the light of the theoretical predictions of Alexander, Courtens and Vacher (ACV) and recent Brillouin scattering results. (C) 1998 Elsevier Science B.V. All rights reserved.

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Documento generato il 02/12/20 alle ore 18:00:59