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Water-in-water PEG/DEX/protein microgel emulsions: Effect of microgel particle size on the rate of emulsion phase separation 
Auteur(s): Balis Andrzej, Gochev Georgi, Truzzolillo D., Lupa Dawid, Szyk-Warszynska Liliana, Zawala Jan
(Article) Publié:
Food Hydrocolloids, vol. 167 p.111425 (2025)
Ref HAL: hal-05036925_v1
DOI: 10.1016/j.foodhyd.2025.111425
Exporter : BibTex | endNote
Résumé: Protein nanoparticles have been proven to be highly effective stabilizers of water-in-water emulsions obtained from a number of different types of aqueous two-phase systems (ATPS). The emulsion stabilizing efficiency of such particles is attributed to their affinity to the water/water interface of relevant ATPS, and emulsion formulations with long-term stability were reported in the recent years. In this study we investigated the macroscopic dynamics of the early-stage time evolution of dextran-in-polyethylene glycol emulsions obtained from a single ATPS and containing β-lactoglobulin microgel particles of various diameters (ca. 40-190 nm). The results revealed the existence of a threshold in microgel size above which the water-in-water emulsion is stabilized, and that the process of segregative phase separation is determined by the interplay of droplets coalescence and sedimentation. Efficient droplet coalescence inhibition was found for microgel particles larger than 60 nm. Based on previous literature results, we discuss our coalescence-driven phase separation data in the context of the formation of durable particle layers on the emulsion droplets and the resulting droplet-droplet interactions.
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Emergence of capillary waves in miscible coflowing fluids
Auteur(s): Carbonaro A., Savorana Giovanni, Cipelletti L., Govindarajan Rama, Truzzolillo D.
(Article) Publié:
Physical Review Letters, vol. 134 p.054001 (2025)
Texte intégral en Openaccess : 
Ref HAL: hal-04930485_v1
Ref Arxiv: 2409.17333
DOI: 10.1103/PhysRevLett.134.054001
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We show that capillary waves can exist at the the boundary between miscible co-flowing fluids. We unveil that the interplay between transient interfacial stresses and confinement drives the progressive transition from the well-known inertial regime, characterized by a frequency independent wavenumber, k ∼ ω 0 , to a capillary wave scaling, k ∼ ω 2/3 , unexpected for miscible fluids. This allows us to measure the effective interfacial tension between miscible fluids and its rapid decay on time scales never probed so far, which we rationalize with a model going beyond square-gradient theories. Our work potentially opens a new avenue to measure transient interfacial tensions at the millisecond scale in a controlled manner.
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