Dr. Veronique Trappe

University of Fribourg, Switzerland

Hallmarks of local intermittent relaxation events in the creep behavior of a colloidal gel

Abstract

 Hallmarks of local intermittent relaxation events
in the creep behavior of a colloidal gel
D. C. E. Calzolari, I. Bischofberger*, F. Nazzani and V. Trappe
University of Fribourg, Department of Physics, CH-1700 Fribourg, Switzerland
*current address: Massachusetts Institute of Technology, Department of Mechanical
Engineering, Cambridge, MA 02139, United States
We explore the dynamical and mechanical characteristics of an evolving gel, aiming in particular
to assess how the gel evolution impacts the creep response of the system. We find that the creep
behavior of the gel is determined by three distinct contributions: an instantaneous elastic, a
delayed elastic and a loss contribution. The systematic investigation of these contributions in
recovery experiments provides evidence that delayed elastic and loss contributions relate to the
same process, namely local intermittent relaxation events that also govern the structural
relaxation of the gel at quiescent conditions. Upon increasing the stress towards the yield stress
our experimental findings suggest that the size of the restructured zones per event increases,
while the rate of intermittent relaxation events remains essentially unchanged.



Date: 19/1/2018
Time:15:00 (coffee & cookies will be served at 14:45)
Place:FORTH Seminar Room 1