Laboratoire Léon Brillouin

UMR12 CEA-CNRS, Bât. 563 CEA Saclay

91191 Gif sur Yvette Cedex, France


Let's scatter neutrons

The yielding transition of soft colloids
L. Cipelletti
L2C University of Montpellier and CNRS, France
Fri, May. 17th 2019, 11:00-12:00
LLB - Bât 563 p15 (Grande Salle), CEA-Saclay

We investigate the yielding transition of dense suspensions of colloids interacting via a soft repulsive potential by simultaneously measuring their mechanical response and microscopic dynamics under an oscillating shear deformation. At low strain amplitude, the system exhibits ultraslow, ballistic dynamics characterized by a compressed exponential relaxation of correlators, similar to those reported for many jammed soft materials at rest.

Upon increasing the strain amplitude, the system undergoes a dynamic transition towards a steady state characterized by fast stretched exponential, diffusive-like relaxations. The dynamic transition coincides with the onset of the non-linear rheological response. While this scenario seems to be generic to soft colloids, the sharpness of the transition appears to depend on the potential details.

We present a simple model that accounts for this dynamic transition.

Contact : Alain MENELLE


Retour en haut