2020/06/08 by Fabio Giavazzi, Veronique Trappe, Roberto Cerbino
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Bubble #Displacement (psychology) #Distribution function #Enhanced Oil Recovery Techniques #Exponential function #Particle (ecology) #Pickering emulsions and particle stabilization #Reciprocal lattice #Relaxation (psychology) #Scaling #Scattering #Surfactants and Colloidal Systems #cond-mat.soft
paper · pdf · doi:10.1088/1361-648x/abb684
J. Phys.: Condens. Matter (2020)
arxiv created 2020/06/08 · openalex created_date 2020/06/19 · openalex publication_date 2020/09/09 · arxiv updated 2020/09/25 · openalex updated_date 2026/08/06
Abstract Intermittent dynamics driven by internal stress imbalances in disordered systems is a fascinating yet poorly understood phenomenon. Here, we study it for a coarsening foam. By exploiting differential dynamic microscopy and particle tracking we determine the dynamical characteristics of the foam at different ages in reciprocal and direct space, respectively. At all wavevectors q investigated, the intermediate scattering function exhibits a compressed exponential decay. However, the access to unprecedentedly small values of q highlights the existence of two distinct regimes for the q -dependence of the foam relaxation rate Γ( q ). At high q , Γ( q ) ∼ q consistent with directionally-persistent and intermittent bubble displacements. At low q , we find the surprising scaling Γ( q ) ∼ q δ , with δ = 1.6 ± 0.2. The analysis of the bubble displacement distribution in real space reveals the existence of a displacement cut-off of the order of the bubble diameter. Introducing such cut-off length in an existing model, describing stress-driven dynamics in disordered systems, fully accounts for the observed behavior in direct and reciprocal space.