Origin of the slow dynamics and the aging of a soft glass

Sylvain Mazoyer (1) , Luca Cipelletti (1) , Laurence Ramos (1)

1 LCVN - Laboratoire des colloïdes, verres et nanomatériaux

We study by light microscopy a soft glass consisting of a compact arrangement of polydisperse elastic spheres. We show that its slow and non-stationary dynamics results from the unavoidable small fluctuations of temperature, which induce intermittent local mechanical shear in the sample, because of thermal expansion and contraction. Temperature-induced shear provokes both reversible and irreversible rearrangements whose amplitude decreases with time, leading to an exponential slowing down of the dynamics with sample age.

Mots clés: 82.70.-y; 61.20.Lc; 61.43.-j; 62.20.Fe

Domaines: Matière Molle [cond-mat.soft]

Sylvain Mazoyer, Luca Cipelletti, Laurence Ramos. Origin of the slow dynamics and the aging of a soft glass. Physical Review Letters, 2006, 97, pp.238301. ⟨hal-00021876v2⟩