Dynamics of a colloid-stabilized cream Auteur(s): Herzig E. M., Robert A., Zand D. D. van 't, Cipelletti L., Pusey P. N., Clegg P. S. (Article) Publié: Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 79 p.011405 (2009) Texte intégral en Openaccess : Ref HAL: hal-00512105_v1 PMID 19257033 Ref Arxiv: 0812.3847 DOI: 10.1103/PhysRevE.79.011405 WoS: 000262976600046 Ref. & Cit.: NASA ADS Exporter : BibTex | endNote 22 Citations Résumé: We use x-ray photon correlation spectroscopy to investigate the dynamics of a high volume fraction emulsion creaming under gravity. The dodecane-in-water emulsion has interfaces stabilized solely by colloidal particles (silica). The samples were observed soon after mixing: as the emulsion becomes compact we discern two regimes of ageing with a cross-over between them. The young emulsion has faster dynamics associated with creaming in a crowded environment accompanied by local rearrangements. The dynamics slow down for the older emulsion although our studies show that motion is associated with large intermittent events. The relaxation rate, as seen from the intensity autocorrelation function, depends linearly on the wave vector at all times; however, the exponent associated with the line shape changes from 1.5 for young samples to less than 1 as the emulsion ages. The combination of ballisticlike dynamics, an exponent that drops below 1 and large intermittent fluctuations has not been reported before. Commentaires: 8 pages, 5 figures |