Microstructure, morphology and lifetime of armored bubbles exposed to surfactants

TL;DR

This study investigates how particle-stabilized armored bubbles change shape, structure, and lifetime when exposed to different surfactant concentrations, revealing the role of interfacial jamming and surfactant effects.

Contribution

It provides new insights into the morphological and microstructural evolution of armored bubbles under surfactant influence, highlighting the interplay of jamming and destabilization mechanisms.

Findings

Low surfactant concentrations keep bubbles non-spherical during dissolution.

High surfactant concentrations cause bubbles to revert to spherical shape before dissolving.

Particle dynamics and interfacial stresses are key to stabilization and destabilization processes.

Abstract

We report the behavior of particle-stabilized bubbles (armored bubbles) when exposed to various classes and concentrations of surfactants. The bubbles are non-spherical due to the jamming of the particles on the interface and are stable to dissolution prior to the addition of surfactant. We find that the dissolving bubbles exhibit distinct morphological, microstructural, and lifetime changes, which correlate with the concentration of surfactant employed. For low concentrations of surfactant an armored bubble remains non-spherical while dissolving, while for concentrations close to and above the surfactant CMC a bubble reverts to a spherical shape before dissolving. We propose a microstructural interpretation, supported by our experimental observations of particle dynamics on the bubble interface, that recognizes the role of interfacial jamming and stresses in particle stabilization and surfactant-mediated destabilization of armored bubbles.