Aging of rotational diffusion in colloidal gels and glasses

S. Jabbari-Farouji 1, 2, G. H. Wegdam 2, Daniel Bonn 3

Physical Review E 86 (2012) 041401

We study the rotational diffusion of aging Laponite suspensions for a wide range of concentrations using depolarized dynamic light scattering. The measured orientational correlation functions undergo an ergodic to non-ergodic transition that is characterized by a concentration-dependent ergodicity-breaking time. We find that the relaxation times associated with rotational degree of freedom as a function of waiting time, when scaled with their ergodicity-breaking time, collapse on two distinct master curves. These master curves are similar to those previously found for the translational dynamics; The two different classes of behavior were attributed to colloidal gels and glasses. Therefore, the aging dynamics of rotational degree of freedom provides another signature of the distinct dynamical behavior of colloidal gels and glasses.

  • 1. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
    CNRS : UMR8626 – Université Paris XI - Paris Sud
  • 2. University of Amsterdam Van der Waals-Zeeman Institute (VAN DER WAALS-ZEEMAN INSTITUTE),
    University of Amsterdam
  • 3. Laboratoire de Physique Statistique de l'ENS (LPS),
    CNRS : UMR8550 – Université Paris VI - Pierre et Marie Curie – Université Paris VII - Paris Diderot – Ecole Normale Supérieure de Paris - ENS Paris