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

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

Domaines: Matière Molle [cond-mat.soft]

Agnes Duri, David A. Sessoms, Veronique Trappe, Luca Cipelletti. Resolving long-ranged spatial correlations in the dynamics of jammed systems. 2008. ⟨hal-00330408v2⟩