Paper Number
VP61 

Session
Pre-recorded Flash Presentations (virtual)

Title
Delayed elastic and ageing creep response of foams

Presentation Date and Time
All Week (Asynchronous) Any Time

Track / Room
Pre-recorded Presentation / Virtual

Authors (Click on name to view author profile)

1. Lavergne, François A. (University of Fribourg, Department of Physics)
2. Sollich, Peter (Georg August University of Göttingen, Faculty of Physics, Institute for Theoretical Physics)
   Sollich, Peter (King's College London, Department of Mathematics)
3. Trappe, Véronique (Fribourg University, Department of Physics)

Author and Affiliation Lines (in printed abstract book)
François A. Lavergne¹, Peter Sollich^2,3 and Véronique Trappe^1
1Department of Physics, University of Fribourg, Fribourg 1700, Switzerland; ²Faculty of Physics, Institute for Theoretical Physics, Georg August University of Göttingen, Göttingen 37077, Germany; ³Department of Mathematics, King's College London, London WC2R 2LS, United Kingdom

Speaker / Presenter 
Lavergne, François A.

Keywords
experimental methods; theoretical methods; foams; glasses; non-Newtonian fluids

Text of Abstract
Liquid foams distinguish themselves among soft jammed materials in that intermittent rearrangements constantly reconfigure the bubble packing. Thus, any small applied stress causes a slow creep deformation beyond the Hookean strain. Here, we show that the creep response comprises two power-law regimes, well separated by a transient relaxation that slows down with waiting time. The short-time branch is quasi-stationary and we identify it as a delayed elastic response, since it is recoverable upon releasing the stress. The other branch is the asymptotic behaviour of a non-stationary contribution to creep and is irreversible. Remarkably, a unique exponent governs both power-laws and the increase of the relaxation time, consistent with ageing in Soft Glassy Rheology just above the glass transition.