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Zawala J, Miguet J, Rastogi P, Atasi O, Borkowski M, Scheid B, Fuller GG. Coalescence of surface bubbles: The crucial role of motion-induced dynamic adsorption layer. Adv Colloid Interface Sci 2023; 317:102916. [PMID: 37269558 DOI: 10.1016/j.cis.2023.102916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 06/05/2023]
Abstract
The formation of motion-induced dynamic adsorption layers of surfactants at the surface of rising bubbles is a widely accepted phenomenon. Although their existence and formation kinetics have been theoretically postulated and confirmed in many experimental reports, the investigations primarily remain qualitative in nature. In this paper we present results that, to the best of our knowledge, provide a first quantitative proof of the influence of the dynamic adsorption layer on drainage dynamics of a single foam film formed under dynamic conditions. This is achieved by measuring the drainage dynamics of single foam films, formed by air bubbles of millimetric size colliding against the interface between n-octanol solutions and air. This was repeated for a total of five different surfactant concentrations and two different liquid column heights. All three steps preceding foam film rupture, namely the rising, bouncing and drainage steps, were sequentially examined. In particular, the morphology of the single film formed during the drainage step was analyzed considering the rising and bouncing history of the bubble. It was found that, depending on the motion-induced state of adsorption layer at the bubble surface during the rising and the bouncing steps, single foam film drainage dynamics can be spectacularly different. Using Direct Numerical Simulations (DNS), it was revealed that surfactant redistribution can occur at the bubble surface as a result of the bouncing dynamics (approach-bounce cycles), strongly affecting the interfacial mobility, and leading to slower rates of foam film drainage. Since the bouncing amplitude directly depends on the rising velocity, which correlates in turn with the adsorption layer of surfactants at the bubble surface during the rising step, it is demonstrated that the lifetime of surface bubbles should intimately be related to the history of their formation.
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Affiliation(s)
- Jan Zawala
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Krakow, Poland; Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
| | - Jonas Miguet
- TIPs, Fluid Physics Unit, Université Libre de Bruxelles, B-1050 Bruxelles, Belgium
| | - Preetika Rastogi
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Chemical Engineering, Indian Institute of Technology, Chennai 600036, Tamil Nadu, India
| | - Omer Atasi
- TIPs, Fluid Physics Unit, Université Libre de Bruxelles, B-1050 Bruxelles, Belgium
| | - Mariusz Borkowski
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Krakow, Poland
| | - Benoit Scheid
- TIPs, Fluid Physics Unit, Université Libre de Bruxelles, B-1050 Bruxelles, Belgium
| | - Gerald G Fuller
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
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Wierenga PA, Basheva ES, Delahaije RJBM. Variations in foam collapse and thin film stability with constant interfacial and bulk properties. Adv Colloid Interface Sci 2023; 312:102845. [PMID: 36709573 DOI: 10.1016/j.cis.2023.102845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023]
Abstract
The stability of foams is commonly linked to the interfacial properties of the proteins and other surfactants used. This study aimed to use these relationships to explain differences in foam stability observed among similar beer samples from different breweries. The foam stability was different for each sample (Nibem foam stability ranged from 206 to 300 s), but ranking was similar for all three foaming methods used, thus independent of the method, gas, etc. Differences in foam stability were dominated by differences in coalescence, as illustrated by the correlation with the stability of single bubbles and thin liquid films. The differences in coalescence stability could not be explained by the measured interfacial properties (e.g. surface pressure, adsorption rate, dilatational modulus and surface shear viscosity), or the bulk properties (concentration, pH, ionic strength, viscosity), since they were similar for all samples. The drainage rates and disjoining pressure isotherms measured in thin liquid films were also similar for all samples, further limiting the options to explain the differences in foam stability using known arguments. The differences in coalescence stability of the thin films was shown to depend on the liquid in between the adsorbed layers of the thin film, using a modified capillary cell to exchange this liquid (to a buffer, or one of the other samples). This illustrates the need to review our current understanding and to develop new methods both for experimental study and theoretical description, to better understand foam stability in the future.
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Affiliation(s)
- Peter Alexander Wierenga
- Laboratory of Food Chemistry, Wageningen UR, Bornse Weilanden 9, Wageningen 6708, WG, the Netherlands.
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Fan J, Zhang J, Yang X, Bai L, Zhou Y, Wu Z, Qin Z. Synthesis and properties of sodium fatty acyl lactylates. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Beyond particle stabilization of emulsions and foams: Proteins in liquid-liquida and liquid-gas interfaces. Adv Colloid Interface Sci 2022; 308:102743. [DOI: 10.1016/j.cis.2022.102743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/04/2022] [Accepted: 07/15/2022] [Indexed: 01/02/2023]
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