Coalescence of Water Drops at an Oil–Water Interface Loaded with Microparticles and Surfactants
| Autor: | Olivier Masbernat, Esteban Calvo, Frédéric Risso, Erik de Malmazet |
|---|---|
| Přispěvatelé: | Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Universidad Zaragoza (SPAIN), Institut de Mécanique des Fluides de Toulouse - IMFT (Toulouse, France), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Institut de mécanique des fluides de Toulouse (IMFT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire de génie chimique [ancien site de Basso-Cambo] (LGC), Institut National Polytechnique de Toulouse - INPT (FRANCE) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Work (thermodynamics)
Materials science General Chemical Engineering Surfactants Interfaces 02 engineering and technology General Chemistry Coalescence Microparticles 021001 nanoscience & nanotechnology Industrial and Manufacturing Engineering Condensed Matter::Soft Condensed Matter Physics::Fluid Dynamics [CHIM.GENI]Chemical Sciences/Chemical engineering 020401 chemical engineering Chemical engineering Pulmonary surfactant Génie chimique Oil water [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering Coalescence (chemistry) 0204 chemical engineering 0210 nano-technology Génie des procédés |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Industrial and engineering chemistry research Industrial and engineering chemistry research, American Chemical Society, 2019, 58 (34), pp.15573-15587. ⟨10.1021/acs.iecr.9b02524⟩ |
| ISSN: | 0888-5885 1520-5045 |
| DOI: | 10.1021/acs.iecr.9b02524⟩ |
| Popis: | This work investigates the coalescence of water droplets settled on a water–oil interface in the presence of microparticles and surfactant. The successive stages of the coalescence process, including interstitial film formation, drainage, rupture, and retraction, are analyzed in detail. This leads us to distinguish between contrasted situations depending on the nature of the surfactant and its affinity with the microparticles. Hydrophilic particles have been previously shown to promote coalescence by means of a bridging mechanism. In that case, coalescence is a deterministic process that lasts the time required for the drainage to make the film thickness equal to the size of the particles. However, the present study shows how surfactants can totally change the effect of the particles upon coalescence. When surfactant both stabilizes the water–oil interface and adsorbs onto the particles, the bridging mechanism is inhibited and the coalescence becomes a random process. Since molecular forces between facing film interfaces are not attractive, thermal fluctuations are required to initiate the formation of a hole in the adsorbed surfactant layer. Provided the surfactant concentration in the bulk is large enough to ensure that the interfaces are close to saturation, the coalescence is delayed by a stochastic time interval and the drop coalescence becomes a Poisson process. These results shed a new light on the mechanisms of droplet coalescence in complex industrial applications where surfactant and particles are present, either purposely added or present as uncontrolled contaminants. |
| Databáze: | OpenAIRE |
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