Coarsening dynamics of three dimensional levitated foams: from wet to dry

TL;DR

This study investigates the coarsening dynamics of diamagnetically levitated foams across different liquid fractions, revealing distinct growth laws and microscopic behaviors for dry and wet regimes.

Contribution

It provides experimental evidence of different coarsening laws and local dynamics in levitated foams, bridging the understanding between dry and wet foam behaviors.

Findings

Dry foams follow a square root growth law consistent with von Neumann law.

Wet foams exhibit 1/3 power growth characteristic of Ostwald ripening.

Diffusing Wave Spectroscopy shows diffusive dynamics in dry foams and kinetic in wet foams.

Abstract

We study diamagnetically levitated foams with widely different liquid fractions. Due to the levitation, drainage is effectively suppressed and the dynamics is driven by the coarsening of the foam bubbles. For dry foams, the bubble size increases as the square root of foam age, as expected from a generalized von Neumann law. At higher liquid content, the behavior changes to that of Ostwald ripening where the bubbles grow with the 1/3 power of the age. Using Diffusing Wave Spectroscopy we study the local dynamics in the different regimes and find diffusive behavior for dry foams and kinetic behavior for wet foams.