Université de Fribourg

Interplay of coarsening, aging, and stress hardening impacting the creep behavior of a colloidal gel

Calzolari, D. C. E. ; Bischofberger, Irmgard ; Nazzani, Francesco ; Trappe, Véronique

In: Journal of Rheology, 2017, vol. 61, no. 4, p. 817–831

We explore the dynamical and mechanical characteristics of an evolving gel in diffusing wave spectroscopy (DWS) and rheometry, aiming to assess how the gel evolution impacts the creep response of the system. Our gel is formed by inducing the aggregation of thermosensitive colloids by a variation in temperature. We find experimental evidence that the long time evolution of this gel is due to...

Université de Fribourg

Revealing the fast atomic motion of network glasses

Ruta, B. ; Baldi, G. ; Chushkin, Y. ; Rufflé, B. ; Cristofolini, L. ; Fontana, Adriano ; Zanatta, M. ; Nazzani, Francesco

In: Nature Communications, 2014, vol. 5, p. -

Still very little is known on the relaxation dynamics of glasses at the microscopic level due to the lack of experiments and theories. It is commonly believed that glasses are in a dynamical arrested state, with relaxation times too large to be observed on human time scales. Here we provide the experimental evidence that glasses display fast atomic rearrangements within a few minutes, even in the...