Delayed elastic contributions to the viscoelastic response of foams

• Main Authors: Lavergne, F.A (Author), Sollich, P. (Author), Trappe, V. (Author)
• Format: Article
• Language: English
• Published: American Institute of Physics Inc. 2022
• Subjects: A: Foams; Coarsening; Creep and recovery tests; Elastic contribution; Elastic response; Foam mechanics; Glass; Glass transition; Mechanical response; Power law fluid; Power-law contribution; Response functions; Viscoelastic response; Viscoelasticity
• Online Access: View Fulltext in Publisher

 We show that the slow viscoelastic response of a foam is that of a power-law fluid with a terminal relaxation. Investigations of the foam mechanics in creep and recovery tests reveal that the power-law contribution is fully reversible, indicative of a delayed elastic response. We demonstrate how this contribution fully accounts for the non-Maxwellian features observed in all tests, probing the linear mechanical response function. The associated power-law spectrum is consistent with soft glassy rheology of systems with mechanical noise temperatures just above the glass transition [Fielding et al., J. Rheol. 44, 323 (2000)] and originates from a combination of superdiffusive bubble dynamics and stress diffusion, as recently evidenced in simulations of coarsening foam [Hwang et al., Nat. Mater. 15, 1031 (2016)]. © 2022 Author(s).