Dissolution Arrest and Stability of Armored Bubbles

TL;DR

This study investigates how armored bubbles maintain nonspherical shapes during dissolution, revealing that particle jamming and interface deformation lead to stable, faceted structures characterized by local energy minima and specific pressure conditions.

Contribution

The paper introduces a numerical simulation approach to analyze the stability and shape evolution of dissolving armored bubbles, highlighting the role of particle jamming and interface deformation.

Findings

Faceted shapes correspond to local energy minima during dissolution.

Stability is linked to the vanishing Laplace overpressure and a positive slope in pressure-volume relation.

Interface deformation reduces mean curvature, aiding bubble stability.

Abstract

Dissolving armored bubbles stabilize with nonspherical shapes by jamming the initially Brownian particles adsorbed on their interfaces. In a gas-saturated solution, these shapes are characterized by planar facets or folds for decreasing ratios of the particle to bubble radii. We perform numerical simulations that mimic dissolution, and show that the faceted shape represents a local minimum of energy during volume reduction. This minimum is marked by the vanishing of the Laplace overpressure $\Delta P$, which together with the existence of a $V$-interval where $d\Delta P/dV>0$ guarantees stability against dissolution. The reduction of $\Delta P$ is due to the saddle-shape deformation of most of the interface which accompanies the reduction in the mean curvature of the interface.