Investigation of $q$-dependent dynamical heterogeneity in a colloidal gel by x-ray photon correlation spectroscopy Auteur(s): Trappe Veronique, Pitard E., Ramos L., Robert Aymeric, Bissig Hugo, Cipelletti L. (Article) Publié: Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 76 p.051404 (2007) Texte intégral en Openaccess : Ref HAL: hal-00133792_v3 PMID 18233656 Ref Arxiv: cond-mat/0702646 DOI: 10.1103/PhysRevE.76.051404 WoS: 000251326100047 Ref. & Cit.: NASA ADS Exporter : BibTex | endNote 73 Citations Résumé: We use time-resolved X-Photon Correlation Spectroscopy to investigate the slow dynamics of colloidal gels made of moderately attractive carbon black particles. We show that the slow dynamics is temporally heterogeneous and quantify its fluctuations by measuring the variance $\chi$ of the instantaneous intensity correlation function. The amplitude of dynamical fluctuations has a non-monotonic dependence on scattering vector $q$, in stark contrast with recent experiments on strongly attractive colloidal gels [Duri and Cipelletti, \textit{Europhys. Lett.} \textbf{76}, 972 (2006)]. We propose a simple scaling argument for the $q$-dependence of fluctuations in glassy systems that rationalizes these findings. Commentaires: Final version published in PRE |