FisMat2017 - Submission - View

Abstract's title: Interplay of coarsening, aging and stress hardening impacting the creep behavior of a colloidal gel
Submitting author: Veronique Trappe
Affiliation: University of Fribourg, Department of Physics
Affiliation Address: Chemin du Musée 3 CH-1700 Fribourg
Country: Switzerland
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Davide Calzolari (University of Fribourg), Irmgard Bischofberger (Massachusetts Institute of Technology), Francesco Nazzani (University of Fribourg)
Abstract

We explore the dynamical and mechanical characteristics of an evolving gel, 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 two distinct processes: a coarsening process that involves the incorporation of mobile particles into the network structure and an aging process that triggers intermittent rearrangement events. While coarsening is the main process governing the evolution of the elastic properties of the gel, aging is the process determining structural relaxation. The combination of both processes in addition to stress hardening governs the creep behavior of the gel, a creep behavior that 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 losses and delayed elastic storage have a common origin, both being due to intermittent local structural relaxation events.