Related papers: Slow viscoelastic relaxation and aging in aqueous …
Using 2D numerical simulations as well as analytical modelling, we show how slow viscoelastic dynamics of aqueous foam are linked to coarsening induced intermittent bubble rearrangements. The macroscopic strain rate is expressed in terms of…
We investigate the ultraslow structural relaxation of ageing foams with rheologically-tunable continuous phases. We probe the bubble dynamics associated with pressure-driven foam coarsening using differential dynamic microscopy, which…
Foams are unstable jammed materials. They evolve over timescales comparable to their "time of use", which makes the study of their destabilisation mechanisms crucial for applications. In practice, many foams are made from viscoelastic…
Under steady shear, a foam relaxes stress through intermittent rearrangements of bubbles accompanied by sudden drops in the stored elastic energy. We use a simple model of foam that incorporates both elasticity and dissipation to study the…
We investigate the mechanical response of an aqueous foam, and its relation to the microscopic rearrangement dynamics of the bubble-packing structure. At rest, even though the foam is coarsening, the rheology is demonstrated to be linear.…
Sheared wet foam, which stores elastic energy in bubble deformations, relaxes stress through bubble rearrangements. The intermittency of bubble rearrangements in foam leads to effectively stochastic drops in stress that are followed by…
Liquid foams are archetypal athermal amorphous solids whose elasticity arises from the jamming of densely packed bubbles. We investigate the stress relaxation of non-ageing liquid foams following flow cessation, using fast X-ray…
Plastic rearrangements play a crucial role in the characterization of soft-glassy materials, such as emulsions and foams. Based on numerical simulations of soft-glassy systems, we study the dynamics of plastic rearrangements at the…
Foams and dense emulsions display complex mechanical behavior, including intermittent rearrangement dynamics, power-law rheology, and slow recovery after perturbation. These effects have long been considered evidence for glassy physics in…
We report on experimental measurements of the flow behavior of a wet, two-dimensional foam under conditions of slow, steady shear. The initial response of the foam is elastic. Above the yield strain, the foam begins to flow. The flow…
External driving leads to the emergence of unique phenomena and properties in soft matter systems. We show that driving quasi-2D foams by mechanical vibration results in significant bubble coalescence, which is enhanced by the continuous…
Pressure-driven coarsening triggers bubble rearrangements in liquid foams. Our experiments show that changing the continuous phase rheology can alter these internal bubble dynamics without influencing the coarsening kinetics. Through bubble…
Aqueous foams coarsen with time due to gas diffusion through the liquid. The mean bubble size grows, and small bubbles vanish. However, coarsening is little understood for foams with an intermediate liquid content, particularly in the…
The plastic flow of a foam results from bubble rearrangements. We study their occurrence in experiments where a foam is forced to flow in 2D: around an obstacle; through a narrow hole; or sheared between rotating disks. We describe their…
In wet liquid foams, slow diffusion of gas through bubble walls changes bubble pressure, volume and wall curvature. Large bubbles grow at the expenses of smaller ones. The smaller the bubble, the faster it shrinks. As the number of bubbles…
Aqueous foams are an important model system that displays coarsening dynamics. Coarsening in dispersions and foams is well understood in the dilute and dry limits, where the gas fraction tends to zero and one, respectively. However, foams…
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,…
When two bubbles submerged in a liquid are brought closely together, the intermediate liquid film separating the bubbles begins to drain. Once the film ruptures, the bubbles coalesce and form a neck that expands with time. The dynamics of…
Foams are ideal model systems to study stress-driven dynamics, as stress-imbalances within the system are continuously generated by the coarsening process, which unlike thermal fluctuations, can be conveniently quantified by optical means.…
We use numerical simulations to study the dynamics of dense assemblies of self-propelled particles in the limit of extremely large, but finite, persistence times. In this limit, the system evolves intermittently between mechanical…