Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 4: Colloidal Fluids
CPP 4.4: Vortrag
Montag, 25. Februar 2008, 15:15–15:30, C 264
Dynamical heterogeneities in attractive colloids — •Annalisa Fierro1, Emanuela Del Gado2, Antonio de Candia1, and Antonio Coniglio1 — 1Dipartimento di Scienze Fisiche, Università di Napoli "Federico II", Italy — 2Polymer Physics, ETH Zürich
Dynamical heterogeneities in glasses are explained in terms of the correlated motion of particles, but their possible connections to any structural feature are still unclear. We study dynamical heterogeneities in colloidal gelation, where a complex slowing down of the dynamics, directly related to the formation of persistent structures, is observed at different volume fractions. By means of Molecular Dynamics simulations of a model colloidal suspension, we have been able to show that, at low volume fractions, the dynamical heterogeneities are in fact dominated by the clusters of long living bonds[1]. This feature is rather similar to the one observed in irreversible gelation, where the presence of dynamical heterogeneities can be explicitly related to the growing mean cluster size [2]. At higher volume fraction, instead, where crowding of the particles starts to be relevant, dynamical heterogeneities show the typical pattern observed in glassy systems. Interestingly, such behavior can be here well described in terms of a suitable mean cluster size of clusters due to finite lifetime bonds [1].
[1] A. Fierro, E. Del Gado, A. de Candia and A. Coniglio, cond-mat/0707.4071. [2] T. Abete, A. de Candia, E. Del Gado, A.Fierro and A. Coniglio, Phys. Rev. Lett. 98, 088301 (2007).