Foamed emulsion drainage: flow and trapping of drops. Issue 22 (30th May 2017)

• Record Type: Journal Article
• Authors: Schneider, Maxime; Zou, Ziqiang; Langevin, Dominique; Salonen, Anniina
• Is Part Of: Soft matter. Volume 13:Issue 22(2017)
• Page Start: 4132
• Page End: 4141
• Publication Date: 2017-05-30
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c7sm00506g
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : The emulsion drains as a homogeneous fluid until blockage, after which it continues to concentrate until complete foam destabilisation starts. Abstract : Foamed emulsions are ubiquitous in our daily life but the ageing of such systems is still poorly understood. In this study we investigate foam drainage and measure the evolution of the gas, liquid and oil volume fractions inside the foam. We evidence three regimes of ageing. During an initial period of fast drainage, both bubbles and drops are very mobile. As the foam stabilises drainage proceeds leading to a gradual decrease of the liquid fraction and slowing down of drainage. Clusters of oil drops are less sheared, their dynamic viscosity increases and drainage slows down even further, until the drops become blocked. At this point the oil fraction starts to increase in the continuous phase. The foam ageing leads to an increase of the capillary pressure until the oil acts as an antifoaming agent and the foam collapses.