Foam Rheology

Origin of the extremely high elasticity of bulk emulsions, stabilized by Yucca Schidigera saponins

“…It is now well recognized that the elasticity of concentrated emulsions and foams is determined by several types of factors, including the volume fraction of the dispersed phase, Φ V , interfacial tension, σ, and average volume-surface radius, R 32 , of the fluid particlesdrops or bubbles (Princen, 2001;Denkov, Tcholakova, Hoehler, & Cohen-Addad, 2012;Mason et al, 1997). The effect of these factors is relatively well understood and described by theoretical expressions, separating the effect of the average capillary pressure, σ/R 32 , from the effect of particle volume fraction, Φ V .…”

“…The predictions of Princen, 2001 model are numerically different, but the conclusions from our study remain the same if we use the latter model. It has been shown by several research groups that two additional factors can also affect strongly the elasticity of concentrated emulsions and foams: (1) The interfacial elasticity of the adsorption layers formed on the drop/bubble surfaces (Dimitrova & Leal-Calderon, 2001;Dimitrova & Leal-Calderon, 2004;Arditty, Schmitt, Giermanska-Kahn, & Leal-Calderon, 2004;Bressy, Hébraud, Schmitt, & Bibette, 2003;Tsibranska et al 2020); and (2) The strength of the adhesion between the neighboring drops (Alben, Holtze, Tadros, & Schurtenberger, 2012;Becu, Manneville, & Colin, 2006) or bubbles (Denkov, Tcholakova, Hoehler, & Cohen-Addad, 2012;Princen, 2001;Politova et al, 2012). Below we analyze the available experimental results, both ours and of other authors, to clarify the relative importance of these two effects and of their combined action.…”

“…Dimitrova & Leal-Calderon, 2004;Arditty, Schmitt, Giermanska-Kahn, & Leal-Calderon, 2004;Bressy, Hébraud, Schmitt, & Bibette, 2003;Tsibranska et al 2020); and (2) The strength of the adhesion between the neighboring drops(Alben, Holtze, Tadros, & Schurtenberger, 2012;Becu, Manneville, & Colin, 2006) or bubbles(Denkov, Tcholakova, Hoehler, & Cohen-Addad, 2012;Princen, 2001;Politova et al, 2012). Below we analyze the available experimental results, both ours and of other authors, to clarify the relative importance of these two effects and of their combined action.…”

Coating particles using liquids and foams based on viscous formulations with industrial mixers: Batch operation

“…It was assumed that the apparent viscosity of big bubble foams was lower than the small bubble foam indicated by the ease to deform them. [41,42] Obtaining information on the rheology of big bubble foams is the subject of current on-going work within the group.…”

Role of interfacial elasticity for the rheological properties of saponin-stabilized emulsions

“…We showed in a previous study [27] that the dilatational and the shear surface elasticities of saponin adsorption layers, formed at the air-water interface, are related in magnitude. In addition, we found [28] that the dilatational elasticity is more relevant for the foam rheological response because the surface area of the bubbles varies under foam shear deformation, which means that the dilatational elasticity of the adsorption layers is important when studying the shear elasticity of foams or emulsions. Therefore, in the current study we first determine the surface dilatational elasticity of the saponin adsorption layers and, afterwards, we use this information to analyse the impact of the dilatational surface elasticity on the rheological properties of emulsions subject to shear deformation.…”