Matrix viscoelasticity decouples bubble growth and dynamics in coarsening foams

TL;DR

This study demonstrates that modifying the rheology of the continuous phase in foams can decouple bubble growth from internal dynamics, affecting foam stability and mechanical properties without altering coarsening rates.

Contribution

It reveals how matrix viscoelasticity influences bubble rearrangements and decouples growth from dynamics in coarsening foams, a novel insight into foam behavior.

Findings

Increasing matrix yield stress allows bubble growth without neighbor-switching.

Decoupling of bubble growth and dynamics affects foam stability.

Structural changes impact mechanical properties of foams.

Abstract

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 tracking, we find that increasing the matrix yield stress permits bubble growth without stress relaxation via neighbor-switching events, promoting more spatially homogeneous rearrangements and decoupling bubble growth from dynamics. This eventually leads to a structural change which directly impacts the foam mechanical and stability properties, essential for applications in various technological and industrial contexts.