Microgels are deformable polymer-networks with conspicuous properties. Their surface- activity associated with their switchability makes their application in liquid-liquid systems, such as extraction processes, particularly promising. For their application as switchable stabilizers at the interface, a detailed understanding of their impact on process relevant phenomena, such as the sedimentation behavior, is necessary. So far, the focus of research has been on microscopic-scale properties, whereby the propagation to macroscopic effects has rarely been quantified. In this study, single microgel-covered n-butyl acetate drops rising in a quiescent continuous water phase are investigated experimentally. The dependency of the microgel properties, in terms of size and cross-linking density, on the fluid dynamics are addressed. The impact of microgels is studied in detail by sedimentation velocity, drop deformation and the resulting drag coefficient. The deformation of drops is related to shape conserving interfacial properties such as the interfacial tension. Counter to our expectations, microgel-covered drops deform less than the drops of the pure system although microgels reduce the interfacial tension. Moreover, the sedimentation velocity is of special interest, since it reveals the mobility of the interface and friction conditions at the interface. Our results demonstrate the correlation between microgel properties at the interface on a microscopic scale and the macroscopic behavior of microgel-covered drops.

Microgels are cross‐linked polymers with a high application potential in liquid‐liquid systems due to their surface activity and switchable stabilization properties. A process concept utilizing microgels in extraction processes is presented. The microgels are located at the drop surface and prevent coalescence, enabling monodisperse operation. At the column top, the stabilization is switched off by temperature shift. The switchable stabilization and the absence of additional mass transfer resistance are crucial requirements for the concept and tested experimentally. The results provide the basis for the model‐based evaluation of the process performance, revealing a broader operating window, capacity increase at equal height equivalent of theoretical stage (HETS) for high loads, and reduced HETS for small loads.