Dresden 2020 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 32: Complex Fluids and Colloids, Micelles and Vesicles (joint session CPP/DY)

DY 32.11: Talk

Wednesday, March 18, 2020, 12:15–12:30, ZEU 114

Emulsion destabilisation by squeeze flow — •Riande Dekker, Antoine Deblais, and Daniel Bonn — Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands

There is a large debate on the destabilisation mechanism of emulsions. We present a simple technique using mechanical compression to destabilise oil-in-water emulsions while at the same time confocal microscopy allows to visualise the mechanism directly. Upon compression of the emulsion, the continuous aqueous phase is squeezed out, while the dispersed oil phase progressively deforms from spherical to honeycomb-like shapes. The liquid films that separate the oil droplets are observed to thin and break at a critical oil/water ratio, leading to coalescence events that destabilise the emulsion. The destabilisation occurs like an avalanche propagating through the system. Local rearrangements occur after the fist destabilisation due to the fist coalescence event. The films participating in the cascade are the finest ones.