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Intermittent dynamics in the aging of jammed systems.
Auteur(s): Cipelletti L.
(Séminaires)
ENS Lyon (Paris, France, FR), 2002-00-00 |
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Dynamique lente, intermittence et vieillissement dans les systemes vitreux moux
Auteur(s): Cipelletti L.
(H.D.R.)
, 2002 |
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Ultraslow dynamics and stress relaxation in the aging of a soft glassy system 
Auteur(s): Ramos L., Cipelletti L.
(Article) Publié:
Physical Review Letters, vol. 87 p.245503 (2001)
Texte intégral en Openaccess : 
Ref HAL: hal-00122195_v1
Ref Arxiv: cond-mat/0109105
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We use linear rheology and multispeckle dynamic light scattering (MDLS) to investigate the aging of a gel composed of multilamellar vesicles. Light scattering data indicate rearrangement of the gel through an unusual ultraslow ballistic motion. A dramatic slowdown of the dynamics with sample age $t_{w}$ is observed for both rheology and MDLS, the characteristic relaxation time scaling as $t_{w}^{\mu}$. We find the same aging exponent $\mu =0.78$ for both techniques, suggesting that they probe similar physical processes, that is the relaxation of applied or internal stresses for rheology or MDLS, respectively. A simple phenomenological model is developed to account for the observed dynamics.
Commentaires: 8 pages, 4 figures
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Universal aging features in the restructuring of fractal colloidal gels
Auteur(s): Cipelletti L., Manley S, Ball Rc, Weitz Da
(Article) Publié:
Physical Review Letters, vol. 84 p.2275-2278 (2000)
Résumé: We use multispeckle dynamic light scattering to measure the dynamic structure factor, f(q, tau), of gels formed by aggregation of colloids. Although the gel is an elastic solid, f(q, tau) nearly completely decays on long time scales, with an unusual form, f(q, tau) similar to exp{-(tau/tau(f))(mu)}, with mu approximate to 1.5 and with tau(f) proportional to q(-1) A model for restructuring of the gel with aging correctly accounts for this behavior. Aging leads to a dramatic increase in tau(f) however, all data can be scaled on a single master curve, with tau(f) asymptotically growing linearly with age. This behavior is strikingly similar to that predicted for aging in disordered glassy systems, offering convincing proof of the universality of these concepts.
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