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Chatzigiannakis E, Vermant J. Dynamic stabilisation during the drainage of thin film polymer solutions. SOFT MATTER 2021; 17:4790-4803. [PMID: 33870979 DOI: 10.1039/d1sm00244a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The drainage and rupture of polymer solutions was investigated using a dynamic thin film balance. The polymeric nature of the dissolved molecules leads to significant resistance to the deformation of the thin liquid films. The influence of concentration, molecular weight, and molecular weight distribution of the dissolved polymer on the lifetime of the films was systematically examined for varying hydrodynamic conditions. Depending on the value of the capillary number and the degree of confinement, different stabilisation mechanisms were observed. For low capillary numbers, the lifetime of the films was the highest for the highly concentrated, narrowly-distributed, low molecular weight polymers. In contrast, at high capillary numbers, the flow-induced concentration differences in the film resulted in lateral osmotic stresses, which caused a dynamic stabilisation of the films and the dependency on molecular weight distribution in particular becomes important. Phenomena such as cyclic dimple formation, vortices, and dimple recoil were observed, the occurrence of which depended on the relative magnitude of the lateral osmotic and the hydrodynamic stresses. The factors which lead to enhanced lifetime of the films as a consequence of these flow instabilities can be used to either stabilise foams or, conversely, prevent foam formation.
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Affiliation(s)
| | - Jan Vermant
- Department of Materials, ETH Zürich, 8032 Zürich, Switzerland.
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Xiang W, Preisig N, Ketola A, Tardy BL, Bai L, Ketoja JA, Stubenrauch C, Rojas OJ. How Cellulose Nanofibrils Affect Bulk, Surface, and Foam Properties of Anionic Surfactant Solutions. Biomacromolecules 2019; 20:4361-4369. [PMID: 31478654 DOI: 10.1021/acs.biomac.9b01037] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We study the generation and decay of aqueous foams stabilized by sodium dodecyl sulfate (SDS) in the presence of unmodified cellulose nanofibrils (CNF). Together with the rheology of aqueous suspensions containing CNF and SDS, the interfacial/colloidal interactions are determined by quartz crystal microgravimetry with dissipation monitoring, surface plasmon resonance, and isothermal titration calorimetry. The results are used to explain the properties of the air/water interface (interfacial activity and dilatational moduli determined from oscillating air bubbles) and of the bulk (steady-state flow, oscillatory shear, and capillary thinning). These properties are finally correlated to the foamability and to the foam stability. The latter was studied as a function of time by monitoring the foam volume, the liquid fraction, and the bubble size distribution. The shear-thinning effect of CNF is found to facilitate foam formation at SDS concentrations above the critical micelle concentration (cSDS ≥ cmc). Compared with foams stabilized by pure SDS, the presence of CNF enhances the viscosity and elasticity of the continuous phase as well as of the air/water interface. The CNF-containing foams have higher liquid fractions, larger initial bubble sizes, and better stability. Due to charge screening effects caused by sodium counter ions and depletion attraction caused by SDS micelles, especially at high SDS concentrations, CNF forms aggregates in the Plateau borders and nodes of the foam, thus slowing down liquid drainage and bubble growth and improving foam stability. Overall, our findings advance the understanding of the role of CNF in foam generation and stabilization.
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Affiliation(s)
- Wenchao Xiang
- Bio-based Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering , Aalto University , P. O. Box 16300, FI-00076 Aalto, Espoo , Finland
| | - Natalie Preisig
- Universität Stuttgart , Institut für Physikalische Chemie , Pfaffenwaldring 55 , 70569 Stuttgart , Germany
| | - Annika Ketola
- VTT Technical Research Centre of Finland Ltd. , P. O. Box 1603, FI-40101 Jyväskylä , Finland
| | - Blaise L Tardy
- Bio-based Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering , Aalto University , P. O. Box 16300, FI-00076 Aalto, Espoo , Finland
| | - Long Bai
- Bio-based Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering , Aalto University , P. O. Box 16300, FI-00076 Aalto, Espoo , Finland
| | - Jukka A Ketoja
- VTT Technical Research Centre of Finland Ltd. , P. O. Box 1000, FI-02044 Espoo , Finland
| | - Cosima Stubenrauch
- Universität Stuttgart , Institut für Physikalische Chemie , Pfaffenwaldring 55 , 70569 Stuttgart , Germany
| | - Orlando J Rojas
- Bio-based Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering , Aalto University , P. O. Box 16300, FI-00076 Aalto, Espoo , Finland
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Boromand A, Signoriello A, Lowensohn J, Orellana CS, Weeks ER, Ye F, Shattuck MD, O'Hern CS. The role of deformability in determining the structural and mechanical properties of bubbles and emulsions. SOFT MATTER 2019; 15:5854-5865. [PMID: 31246221 DOI: 10.1039/c9sm00775j] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We perform computational studies of jammed particle packings in two dimensions undergoing isotropic compression using the well-characterized soft particle (SP) model and deformable particle (DP) model that we developed for bubbles and emulsions. In the SP model, circular particles are allowed to overlap, generating purely repulsive forces. In the DP model, particles minimize their perimeter, while deforming at fixed area to avoid overlap during compression. We compare the structural and mechanical properties of jammed packings generated using the SP and DP models as a function of the packing fraction ρ, instead of the reduced number density φ. We show that near jamming onset the excess contact number Δz = z - zJ and shear modulus G scale as Δρ0.5 in the large system limit for both models, where Δρ = ρ - ρJ and zJ ≈ 4 and ρJ ≈ 0.842 are the values at jamming onset. Δz and G for the SP and DP models begin to differ for ρ ⪆ 0.88. In this regime, Δz ∼ G can be described by a sum of two power-laws in Δρ, i.e. Δz ∼ G ∼ C0Δρ0.5 + C1Δρ1.0 to lowest order. We show that the ratio C1/C0 is much larger for the DP model compared to that for the SP model. We also characterize the void space in jammed packings as a function of ρ. We find that the DP model can describe the formation of Plateau borders as ρ → 1. We further show that the results for z and the shape factor A versus ρ for the DP model agree with recent experimental studies of foams and emulsions.
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Affiliation(s)
- Arman Boromand
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA. and Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Alexandra Signoriello
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA
| | - Janna Lowensohn
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Carlos S Orellana
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Eric R Weeks
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Fangfu Ye
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Mark D Shattuck
- Benjamin Levich Institute and Physics Department, The City College of New York, New York, New York 10031, USA
| | - Corey S O'Hern
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA. and Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA and Department of Physics, Yale University, New Haven, Connecticut 06520, USA and Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA.
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Drenckhan W, Hutzler S. Structure and energy of liquid foams. Adv Colloid Interface Sci 2015; 224:1-16. [PMID: 26233494 DOI: 10.1016/j.cis.2015.05.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/22/2015] [Accepted: 05/23/2015] [Indexed: 11/16/2022]
Abstract
We present an overview of recent advances in the understanding of foam structure and energy and their dependence on liquid volume fraction. We consider liquid foams in equilibrium for which the relevant energy is surface energy. Measurements of osmotic pressure can be used to determine this as a function of liquid fraction in good agreement with results from computer simulations. This approach is particularly useful in the description of foams with high liquid content, so-called wet foams. For such foams X-ray tomography proves to be an important technique in analysing order and disorder. Much of the discussion in this article is also relevant to bi-liquid foams, i.e. emulsions, and to solid foams, provided that the solidification preserves the structure of the initially liquid foam template.
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Affiliation(s)
- Wiebke Drenckhan
- Laboratoire de Physique des Solides, Université de Paris-Sud, CNRS UMR 8502, Orsay, France.
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Vandewalle N, Noirhomme M, Schockmel J, Mersch E, Lumay G, Terwagne D, Dorbolo S. Hysteretic behavior in three-dimensional soap film rearrangements. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:021403. [PMID: 21405845 DOI: 10.1103/physreve.83.021403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Indexed: 05/30/2023]
Abstract
We report experiments on soap film configurations in a triangular prism for which the shape factor can be changed continuously. Two stable configurations can be observed for a range of the shape factor h, being the prism-height/edge-length ratio. A hysteretic behavior is found, due to the occurrence of another local minima in the free energy. Contrary to a common belief, soap films can be trapped in a particular configuration being different from a global surface minimization. This metastability can be evidenced from a geometrical model based on idealized structures. Depending on the configuration, the transition is either first or second order, providing clues on the structural relaxations taking place into three-dimensional foams, such as T1 rearrangements.
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Affiliation(s)
- N Vandewalle
- GRASP, Physics Department, University of Liège, B-4000 Liège, Belgium
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Surenjav E, Priest C, Herminghaus S, Seemann R. Manipulation of gel emulsions by variable microchannel geometry. LAB ON A CHIP 2009; 9:325-330. [PMID: 19107292 DOI: 10.1039/b808160c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this article we investigate the morphology and manipulation of monodisperse emulsions at high dispersed phase volume fractions (gel emulsions) in a microfluidic environment. Confined monodisperse gel emulsions self-organize into well-ordered droplet arrangements, which may be stable or metastable, depending on the geometry of the confining microchannel. Three arrangements are considered, in which the droplets are aligned in a single file, a two row, or a three row arrangement. We explore the potential for induced transitions between these distinct droplet arrangements as a tool for droplet-based microfluidic processing. Transitions are readily achieved by means of localized (geometrical) features in channel geometry, however the onset of the transition is strongly dependent on the subtleties of the microfluidic system, e.g. volume fraction, droplet size, and feature dimensions. The transitions can be achieved via fixed channel features or, when the continuous phase is a ferrofluid, by a virtual channel constriction created using a magnetic field.
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Affiliation(s)
- Enkhtuul Surenjav
- Max Planck Institute for Dynamics and Self-Organization, D-37073, Göttingen, Germany
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Hutzler S, Saadatfar M, van der Net A, Weaire D, Cox S. The dynamics of a topological change in a system of soap films. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2007.11.060] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Rosa ME, Fortes M. Instabilities and transitions in the deformation of a prismatic bubble. Colloids Surf A Physicochem Eng Asp 2007. [DOI: 10.1016/j.colsurfa.2007.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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