Ultralong-ranged spatial correlations of the dynamics of jammed systems

Agnes Duri (1) , David A. Sessoms (2) , Veronique Trappe (2) , Luca Cipelletti (1)

1 LCVN - Laboratoire des colloïdes, verres et nanomatériaux
2 FRIBPHYS - Physics Department

We introduce a dynamic light scattering method, termed Space and Time Resolved Correlation (STRC), which enables us to resolve the dynamics of soft materials in space and time. We demonstrate STRC by investigating the slow dynamics of two jammed systems, a quasi two-dimensional foam made of deformable bubbles and a rigid gel network formed by strongly attractive colloidal particles. We find the dynamics of both systems to be determined by intermittent rearrangement events. For the foam, the events extend over a few bubble sizes, but a small, finite dynamical correlation is observed up to macroscopic length scales. For the gel, rearrangement events involve correlated motion over surprisingly large distances, comparable to the system size. These results indicate that dynamical correlations in jammed systems can be extremely long-ranged and point to the key role of mechanical properties in determining dynamical correlations.

Mots clés: jamming; light scattering; dynamical heterogeneity; slow dynamics

Domaines: Matière Molle [cond-mat.soft]

Agnes Duri, David A. Sessoms, Veronique Trappe, Luca Cipelletti. Ultralong-ranged spatial correlations of the dynamics of jammed systems. 2008. ⟨hal-00330408v1⟩