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Shi Y, Wang D, Xiao Y, Pan T, Liu W, Lee LP, Xin H, Li B. Spontaneous Particle Ordering, Sorting, and Assembly on Soap Films. NANO LETTERS 2024; 24:6433-6440. [PMID: 38747334 DOI: 10.1021/acs.nanolett.4c01840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Soap bubbles exhibit abundant fascinating phenomena throughout the entire life of evolution with different fundamental physics governing them. Nevertheless, the complicated dynamics of small objects in soap films are still unrevealed. Here, we report the first observation of spontaneous particle ordering in a complicated galaxy of soap films without any external energy. The balance of interfacial tension at two liquid-gas interfaces is theoretically predicted to govern belted wetted particles (BWPs) traveling along a specified path spontaneously. Such spontaneous particle path-finding is found to depend on the particle size and hydrophilic properties. Spontaneous particle sorting is directly realized via these discrete and distinctive paths for different particles. The deformation of the soap membrane facilitates 1D/2D particle organization along the path. This observation represents the discovery of a new spontaneous order phenomenon in soap film systems and provides a new energy-free approach for particle separation and soft colloidal crystal assembly.
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Affiliation(s)
- Yang Shi
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, People's Republic of China
| | - Danning Wang
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, People's Republic of China
| | - Yuqing Xiao
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, People's Republic of China
| | - Ting Pan
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, People's Republic of China
| | - Wenpeng Liu
- Renal Division and Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard University, Boston, Massachusetts 02115, United States
| | - Luke P Lee
- Renal Division and Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard University, Boston, Massachusetts 02115, United States
- Department of Bioengineering, Department of Electrical Engineering and Computer Science, University of California, Berkeley, California 94720, United States
- Institute of Quantum Biophysics, Department of Biophysics, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Hongbao Xin
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, People's Republic of China
| | - Baojun Li
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, People's Republic of China
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2
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Ashrafizadeh SN, Ganjizade A. Liquid foams: Properties, structures, prevailing phenomena and their applications in chemical/biochemical processes. Adv Colloid Interface Sci 2024; 325:103109. [PMID: 38367337 DOI: 10.1016/j.cis.2024.103109] [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: 08/11/2023] [Revised: 12/12/2023] [Accepted: 02/12/2024] [Indexed: 02/19/2024]
Abstract
Liquid foams are gas-liquid dispersions with flexible structures that provide high gas-liquid interfaces. This property nominates liquid foams as excellent gas-liquid contactors, systems that are widely used in the chemical and biochemical industries. However, challenges such as a lack of comprehensive understanding and foam instability have historically hindered their widespread industrial use in most applications. It was not until the recent development of nanofluidics, nanotechnology, surface science, and other related fields that the understanding, analysis, and control of foam phenomena improved. This led to the development of innovative stabilization techniques and foam-based unit operations in chemical and biochemical processes, each of which requires in-depth and exclusive reviews to fully comprehend their potential and limitations and to identify areas for further improvement and innovation. This paper reviews the foams, the common phenomena in them, the characteristics that make them suitable for chemical/biochemical engineering, reports on their current applications and recent developments in this field.
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Affiliation(s)
- Seyed Nezameddin Ashrafizadeh
- Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
| | - Ardalan Ganjizade
- Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
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3
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Vinogradova OI, Silkina EF. Electrophoresis of ions and electrolyte conductivity: From bulk to nanochannels. J Chem Phys 2023; 159:174707. [PMID: 37933780 DOI: 10.1063/5.0168557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/16/2023] [Indexed: 11/08/2023] Open
Abstract
When electrolyte solutions are confined in micro- and nanochannels their conductivity is significantly different from those in a bulk phase. Here we revisit the theory of this phenomenon by focusing attention on the reduction in the ion mobility with the concentration of salt and a consequent impact to the conductivity of a monovalent solution, from bulk to confined in a narrow slit. We first give a systematic treatment of electrophoresis of ions and obtain equations for their zeta potentials and mobilities. The latter are then used to obtain a simple expression for a bulk conductivity, which is valid in a concentration range up to a few molars and more accurate than prior analytic theories. By extending the formalism to the electrolyte solution in the charged channel the equations describing the conductivity in different modes are presented. They can be regarded as a generalization of prior work on the channel conductivity to a more realistic case of a nonzero reduction of the electrophoretic mobility of ions with salt concentration. Our analysis provides a framework for interpreting measurements on the conductivity of electrolyte solutions in the bulk and in narrow channels.
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Affiliation(s)
- Olga I Vinogradova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119071 Moscow, Russia
| | - Elena F Silkina
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119071 Moscow, Russia
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4
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Fauvel M, Trybala A, Tseluiko D, Starov VM, Bandulasena HCH. Foam-Based Electrophoretic Separation of Charged Dyes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13935-13942. [PMID: 36322953 PMCID: PMC9671044 DOI: 10.1021/acs.langmuir.2c02228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Electrophoretic separation of a fluorescent dye mixture, containing rhodamine B (RB) and fluorescein, in liquid foams stabilized by anionic, cationic, or non-ionic surfactants in water-glycerol mixtures was studied in a custom-designed foam separation device. The effects of the external electric field applied across the foam and the initial pH of the solution on the effectiveness of separation were also studied. The fluid motion due to electroosmosis and the resulting back pressure within the foam and local pH changes were found to be complex and affected the separation. Fluorescein dye molecules, which have a positive or negative charge depending on the solution pH, aggregated in the vicinity of an electrode, leaving a pure band of neutral dye RB. The effectiveness of the separation was quantified by the percentage width of the pure RB band, which was found to be between 29 and 42%. This study demonstrates the potential of liquid foam as a platform for electrophoretic separation.
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Affiliation(s)
- Matthieu Fauvel
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Anna Trybala
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Dmitri Tseluiko
- Department
of Mathematics, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Victor Mikhilovich Starov
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
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5
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Fauvel M, Trybala A, Tseluiko D, Starov VM, Bandulasena HCH. Stability of Two-Dimensional Liquid Foams under Externally Applied Electric Fields. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6305-6321. [PMID: 35546544 PMCID: PMC9134501 DOI: 10.1021/acs.langmuir.2c00026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/26/2022] [Indexed: 06/15/2023]
Abstract
Liquid foams are highly complex systems consisting of gas bubbles trapped within a solution of surfactant. Electroosmotic effects may be employed to induce fluid flows within the foam structure and impact its stability. The impact of external electric fields on the stability of a horizontally oriented monolayer of foam (2D foam) composed of anionic, cationic, non-ionic, and zwitterionic surfactants was investigated, probing the effects of changing the gas-liquid and solid-liquid interfaces. Time-lapse recordings were analyzed to investigate the evolution of foam over time subject to varying electric field strengths. Numerical simulations of electroosmotic flow of the same system were performed using the finite element method. Foam stability was affected by the presence of an external electric field in all cases and depended on the surfactant type, strength of the electric field, and the solid material used to construct the foam cell. For the myristyltrimethylammonium bromide (MTAB) foam in a glass cell, the time to collapse 50% of the foam was increased from ∼25 min under no electric field to ∼85 min under an electric field strength of 2000 V/m. In comparison, all other surfactants trialed exhibited faster foam collapse under external electric fields. Numerical simulations provided insight as to how different zeta potentials at the gas-liquid and solid-liquid interfaces affect fluid flow in different elements of the foam structure under external electric fields, leading to a more stable or unstable foam.
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Affiliation(s)
- Matthieu Fauvel
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, United Kingdom
| | - Anna Trybala
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, United Kingdom
| | - Dmitri Tseluiko
- Department
of Mathematics, Loughborough University, Loughborough, Leicestershire, LE11 3TU, United Kingdom
| | - Victor Mikhilovich Starov
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, United Kingdom
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Ye Z, Yang J, Su H, Lian C, Shang Y, Liu H. Flow effects on the surface properties of surfactant foam films. Phys Chem Chem Phys 2021; 23:26761-26767. [PMID: 34846391 DOI: 10.1039/d1cp03279h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The surface electrostatic properties of liquid foam, involving the electrokinetic (EK) phenomena in the liquid-gas interface, have significant effects on the stability of the foam. Here, we established a theoretical model for ion transport in liquid films by combining the liquid flow and surface reaction. We found that the surface electrostatic properties of liquid foams were influenced unexpectedly by the pressure-induced flow. The liquid flow will induce the potential and concentration differences in the flow direction. When the pressure drop increases to a certain high value, the induced potential and salt concentration difference increases, leading to the change of the surface electrostatic properties such as zeta potential and the surface charge density. This change shows that the surface electrostatic properties of foam films depend on the coupling of various factors including ion distribution and pressure drop, which deepens our understanding of the electrostatic properties of the foam films.
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Affiliation(s)
- Zhicheng Ye
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
| | - Jie Yang
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
| | - Haiping Su
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
| | - Cheng Lian
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China. .,State Key Laboratory of Chemical Engineering, Shanghai Engineering Research Center of Hierarchical Nanomaterials, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Yazhuo Shang
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
| | - Honglai Liu
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China. .,State Key Laboratory of Chemical Engineering, Shanghai Engineering Research Center of Hierarchical Nanomaterials, East China University of Science and Technology, Shanghai 200237, P. R. China
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7
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Vinogradova OI, Silkina EF, Asmolov ES. Enhanced transport of ions by tuning surface properties of the nanochannel. Phys Rev E 2021; 104:035107. [PMID: 34654173 DOI: 10.1103/physreve.104.035107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/05/2021] [Indexed: 11/07/2022]
Abstract
Motivated by recent observations of anomalously large deviations of the conductivity currents in confined systems from the bulk behavior, we revisit the theory of ion transport in parallel-plate channels and also discuss how the wettability of a solid and the mobility of adsorbed surface charges impact the transport of ions. It is shown that depending on the ratio of the electrostatic disjoining pressure to the excess osmotic pressure at the walls two different regimes occur. In the thick channel regime this ratio is small and the channel effectively behaves as thick, even when the diffuse layers strongly overlap. The latter is possible for highly charged channels only. In the thin channel regime the disjoining pressure is comparable to the excess osmotic pressure at the wall, which implies relatively weakly charged walls. We derive simple expressions for the mean conductivity of the channel in these two regimes, highlighting the role of electrostatic and electrohydrodynamic boundary conditions. Our theory provides a simple explanation of the high conductivity observed experimentally in hydrophilic channels, and allows one to obtain rigorous bounds on its attainable value and scaling with salt concentration. Our results also show that further dramatic amplification of conductivity is possible if hydrophobic slip is involved, but only in the thick channel regime provided the walls are sufficiently highly charged and most of the adsorbed charges are immobile. However, for weakly charged surfaces the massive conductivity amplification due to hydrodynamic slip is impossible in both regimes. Interestingly, in this case the moderate slip-driven contribution to conductivity can monotonously decrease with the fraction of immobile adsorbed charges. These results provide a framework for tuning the conductivity of nanochannels by adjusting their surface properties and bulk electrolyte concentrations.
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Affiliation(s)
- Olga I Vinogradova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119071 Moscow, Russia
| | - Elena F Silkina
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119071 Moscow, Russia
| | - Evgeny S Asmolov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119071 Moscow, Russia
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8
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Amani P, Karakashev SI, Grozev NA, Simeonova SS, Miller R, Rudolph V, Firouzi M. Effect of selected monovalent salts on surfactant stabilized foams. Adv Colloid Interface Sci 2021; 295:102490. [PMID: 34385000 DOI: 10.1016/j.cis.2021.102490] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/15/2021] [Accepted: 07/18/2021] [Indexed: 12/11/2022]
Abstract
Surfactant-stabilized foams have been at the centre of scientific research for over a century due to their ubiquitous applications in different industries. Many of these applications involve inorganic salts either due to their natural presence (e.g. use of seawater in froth floatation) or their addition (e.g. in cosmetics) to manipulate foam characteristics for the best outcomes. This paper provides a clear understanding of the effect of salts on surfactant-stabilized foams through a critical literature survey of this topic. Available literature shows a double effect of salts (LiCl, NaCl and KCl) on foam characteristics in the presence of surfactants. To elucidate the underlying mechanisms of the stabilizing effect of salts on foams, the effect of salts on surfactant-free thin liquid films is first discussed, followed by a discussion on the effect of salts on surfactant-stabilized foams with the focus on anionic surfactants. We discuss two distinctive salt concentrations, salt transition concentration in surfactant-free solutions and salt critical concentration in surfactant-laden systems to explain their effects. Using the available data in literature supported by dedicated experiments, we demonstrate the destabilizing effect of salts on foams at and above their critical concentrations in the presence of anionic surfactants. This effect is attributed to retarding the adsorption of the surfactant molecules at the interface due to the formation of nano and micro-scale aggregates.
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Affiliation(s)
- Pouria Amani
- School of Chemical Engineering, The University of Queensland, St. Lucia 4072, Australia
| | | | - Nikolay A Grozev
- Department of Physical Chemistry, University of Sofia, Sofia 1164, Bulgaria
| | | | - Reinhard Miller
- Department of Physics, Technische Universität Darmstadt, Darmstadt 64289, Germany
| | - Victor Rudolph
- School of Chemical Engineering, The University of Queensland, St. Lucia 4072, Australia
| | - Mahshid Firouzi
- Newcastle Institute for Energy and Resources, The Uniersity of Newcastle, Callaghan 2308, Australia.
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9
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Hussein Sheik A, Montazersadgh F, Starov VM, Trybala A, Wijayantha KGU, Bandulasena HCH. Electrokinetic Transport of a Charged Dye in a Freely Suspended Liquid Film: Experiments and Numerical Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:1183-1191. [PMID: 31957457 DOI: 10.1021/acs.langmuir.9b03852] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electrokinetic transport of a charged dye within a free liquid film stabilized by a cationic surfactant, trimethyl(tetradecyl)ammonium bromide, subjected to an external electric field was investigated. Confocal laser scanning microscopy was used to visualize fluorescein isothiocyanate (FITC) separation within the stabilized liquid film. Numerical simulations were performed using the finite element method to model the dynamics of charged dye separation fronts observed in the experiments. Because of the electrochemical reactions at the electrodes, significant spatial and temporal pH changes were observed within the liquid film. These local pH changes could affect the local zeta potential at the gas-liquid and solid-liquid film boundaries; hence, the flow field was found to be highly dynamic and complex. The charged dye (FITC) used in the experiments is pH-sensitive, and therefore, electrophoresis of the dye also depended on the local pH. The pH and the electroosmotic flow field predicted from the numerical simulations were useful for understanding charged dye separation near both the anode and the cathode.
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Affiliation(s)
| | - Faraz Montazersadgh
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering , Loughborough University , Loughborough LE11 3TU , U.K
| | | | - Anna Trybala
- Department of Chemical Engineering , Loughborough University , Loughborough LE11 3TU , U.K
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10
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Fu L, Joly L, Merabia S. Giant Thermoelectric Response of Nanofluidic Systems Driven by Water Excess Enthalpy. PHYSICAL REVIEW LETTERS 2019; 123:138001. [PMID: 31697539 DOI: 10.1103/physrevlett.123.138001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 07/11/2019] [Indexed: 06/10/2023]
Abstract
Nanofluidic systems could in principle be used to produce electricity from waste heat, but current theoretical descriptions predict a rather poor performance as compared to thermoelectric solid materials. Here we investigate the thermoelectric response of NaCl and NaI solutions confined between charged walls, using molecular dynamics simulations. We compute a giant thermoelectric response, 2 orders of magnitude larger than the predictions of standard models. We show that water excess enthalpy-neglected in the standard picture-plays a dominant role in combination with the electro-osmotic mobility of the liquid-solid interface. Accordingly, the thermoelectric response can be boosted using surfaces with large hydrodynamic slip. Overall, the heat harvesting performance of the model systems considered here is comparable to that of the best thermoelectric materials, and the fundamental insight provided by molecular dynamics suggests guidelines to further optimize the performance, opening the way to recycle waste heat using nanofluidic devices.
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Affiliation(s)
- Li Fu
- Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Laurent Joly
- Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Samy Merabia
- Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
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11
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Duignan TT, Peng M, Nguyen AV, Zhao XS, Baer MD, Mundy CJ. Detecting the undetectable: The role of trace surfactant in the Jones-Ray effect. J Chem Phys 2018; 149:194702. [DOI: 10.1063/1.5050421] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Timothy T. Duignan
- School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane 4072, Australia
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Mengsu Peng
- School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane 4072, Australia
| | - Anh V. Nguyen
- School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane 4072, Australia
| | - X. S. Zhao
- School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane 4072, Australia
| | - Marcel D. Baer
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Christopher J. Mundy
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, USA
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12
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Hussein Sheik A, Montazersadgh F, Starov V, Trybala A, Bandulasena HH. Procedures used in electrokinetic investigations of surfactant-laden interfaces, liquid films and foam system. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2018.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Blanc B, Bonhomme O, Brevet PF, Benichou E, Ybert C, Biance AL. Electroosmosis near surfactant laden liquid-air interfaces. SOFT MATTER 2018; 14:2604-2609. [PMID: 29492490 DOI: 10.1039/c7sm02508d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Generation of an electroosmostic (EO) flow near a liquid-gas interface covered with ionic surfactants is experimentally investigated. A combination of microscopic flow measurements with a molecular characterization of the interface by second harmonic generation (SHG) shows that under an electrical forcing, although a liquid flow is generated below the free surface, the surfactants remain immobile. The zeta potential was then determined and compared to the surfactant surface coverage. This combination of experimental techniques opens the route to simultaneously probe the liquid flow near a soapy interface and the corresponding surfactant repartition affecting the hydrodynamic boundary condition.
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Affiliation(s)
- Baptiste Blanc
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, Villeurbanne, F-69622, France.
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14
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Mollaei S, Nasiri M, Soltanmohammadi N, Shirsavar R, Ramos A, Amjadi A. Soap-film flow induced by electric fields in asymmetric frames. Phys Rev E 2018; 97:043110. [PMID: 29758613 DOI: 10.1103/physreve.97.043110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Indexed: 11/07/2022]
Abstract
Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.
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Affiliation(s)
- S Mollaei
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran
| | - M Nasiri
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran
| | - N Soltanmohammadi
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran
| | - R Shirsavar
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran and Department of Physics, Sharif University of Technology, Tehran P.O. Box 11365-9161, Iran
| | - A Ramos
- Departamento de Electrónica y Electromagnetismo, Facultad de Física, Universidad de Sevilla, Seville 41012, Spain
| | - A Amjadi
- Department of Physics, Sharif University of Technology, Tehran P.O. Box 11365-9161, Iran
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15
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Electroosmotic Flow in Free Liquid Films: Understanding Flow in Foam Plateau Borders. COLLOIDS AND INTERFACES 2018. [DOI: 10.3390/colloids2010008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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