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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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2
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Self-assembly of the surfactant mixtures on graphene in the presence of electrolyte: a molecular simulation study. ADSORPTION 2020. [DOI: 10.1007/s10450-020-00264-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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3
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Hamon JJ, Tabor RF, Striolo A, Grady BP. Atomic Force Microscopy Force Mapping Analysis of an Adsorbed Surfactant above and below the Critical Micelle Concentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7223-7239. [PMID: 29807434 DOI: 10.1021/acs.langmuir.8b00574] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Force curves collected using an atomic force microscope (AFM) in the presence of adsorbed surfactants are often used to draw conclusions about adsorbed film packing, rigidity, and thickness. However, some noteworthy features of such force curve characteristics have yet to be thoroughly investigated and explained. In this work, we collected force curves from tetradecyltrimethylammonium bromide films adsorbed on highly oriented pyrolytic graphite (HOPG), silica, and silica that had been hydrophobized by functionalization with dichlorodimethyl silane. Breakthrough events in the force curves from several different trials were compared to show that the breakthrough distance, often reported as the adsorbed film thickness, increased with concentration below the critical micelle concentration (CMC) but was approximately 3.5 nm on all surfaces between 2× and 10× CMC; an unexpected result because of the different surface chemistries for the three surfaces. We employed an AFM probe with a different force constant ( k) value as well as a colloidal probe and the breakthrough distance remained approximately 3.5 nm in all cases. Gradient mapping, a variant of force mapping, was also implemented on the three surfaces and resulted in a new technique for visualizing adsorbed surfactant in situ. The resulting maps showed patches of adsorbed surfactant below the CMC and revealed that with increasing concentration, the size of the patches increased resulting in full coverage near and above the CMC. These results are, to our knowledge, the first time force mapping has been used to spatially track patches of adsorbed surfactant. Finally, layers of surfactants on an AFM tip were investigated by collecting a force map on a single AFM tip using the tip of a separate AFM probe. A breakthrough event was observed between the tips, indicating that a layer of surfactant was present on at least one, if not both tips.
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Affiliation(s)
- J J Hamon
- School of Chemical, Biological and Materials Engineering and Institute of Applied Surfactant Research , University of Oklahoma , Norman , Oklahoma 73019 , United States
| | - Rico F Tabor
- School of Chemistry , Monash University , Wellington Road , Clayton , Victoria 3800 , Australia
| | - Alberto Striolo
- Department of Chemical Engineering , University College London , London WC1E 7JE , U.K
| | - Brian P Grady
- School of Chemical, Biological and Materials Engineering and Institute of Applied Surfactant Research , University of Oklahoma , Norman , Oklahoma 73019 , United States
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4
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Li H, Somers AE, Howlett PC, Rutland MW, Forsyth M, Atkin R. Addition of low concentrations of an ionic liquid to a base oil reduces friction over multiple length scales: a combined nano- and macrotribology investigation. Phys Chem Chem Phys 2016; 18:6541-7. [DOI: 10.1039/c5cp07061a] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The efficacy of ionic liquids (ILs) as lubricant additives to a model base oil has been probed at the nanoscale and macroscale as a function of IL concentration using the same materials.
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Affiliation(s)
- Hua Li
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | | | | | - Mark W. Rutland
- School of Chemical Science and Engineering
- KTH Royal Institute of Technology
- SE100 44, Sweden
- Chemistry
- Materials and Surfaces
| | - Maria Forsyth
- Institute for Frontier Materials
- Deakin University
- Geelong
- Australia
| | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
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Li H, Cooper PK, Somers AE, Rutland MW, Howlett PC, Forsyth M, Atkin R. Ionic Liquid Adsorption and Nanotribology at the Silica-Oil Interface: Hundred-Fold Dilution in Oil Lubricates as Effectively as the Pure Ionic Liquid. J Phys Chem Lett 2014; 5:4095-4099. [PMID: 26278938 DOI: 10.1021/jz5021422] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The remarkable physical properties of ionic liquids (ILs) make them potentially excellent lubricants. One of the challenges for using ILs as lubricants is their high cost. In this article, atomic force microscopy (AFM) nanotribology measurements reveal that a 1 mol % solution of IL dissolved in an oil lubricates the silica surface as effectively as the pure IL. The adsorption isotherm shows that the IL surface excess need only be approximately half of the saturation value to prevent surface contact and effectively lubricate the sliding surfaces. Using ILs in this way makes them viable for large-scale applications.
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Affiliation(s)
- Hua Li
- †Centre for Advanced Particle Processing and Transport, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Peter K Cooper
- †Centre for Advanced Particle Processing and Transport, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Anthony E Somers
- ‡ARC Centre of Excellence for Electromaterials Science, Institute for Frontier Materials, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia
| | - Mark W Rutland
- §School of Chemical Science and Engineering, KTH Royal Institute of Technology, Stockholm SE100 44, Sweden
- ⊥Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Stockholm SE100 44, Sweden
| | - Patrick C Howlett
- ‡ARC Centre of Excellence for Electromaterials Science, Institute for Frontier Materials, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia
| | - Maria Forsyth
- ‡ARC Centre of Excellence for Electromaterials Science, Institute for Frontier Materials, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia
| | - Rob Atkin
- †Centre for Advanced Particle Processing and Transport, The University of Newcastle, Callaghan, New South Wales 2308, Australia
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6
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Liu S, Wu B, Yang X. Electrolyte-induced reorganization of SDS self-assembly on graphene: a molecular simulation study. ACS APPLIED MATERIALS & INTERFACES 2014; 6:5789-5797. [PMID: 24670893 DOI: 10.1021/am5006095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A molecular dynamics simulation was conducted to study the structure and morphology of sodium dodecyl sulfate (SDS) surfactants adsorbed on a nanoscale graphene nanostructure in the presence of an electrolyte. The self-assembly structure can be reorganized by the electrolyte-induced effect. An increase in the ionic strength of the added electrolyte can enhance the stretching of adsorbed surfactants toward the bulk aqueous phase and make headgroups assemble densely, leading to a more compact structure of the SDS/graphene composite. The change in the self-assembly structure is attributed to the accumulation/condensation of electrolyte cations near the surfactant aggregate, consequently screening the electrostatic repulsion between charged headgroups. The role of the electrolyte revealed here provides direct microscopic evidence or an explanation of the reported experiments in the electrolyte tuning of the interfacial structure of a surfactant aggregate on the surface of carbon nanoparticles. Additionally, the buoyant density of the SDS/graphene assembly has been computed. With an increase in the ionic strength of the electrolyte, the buoyant density of the SDS/graphene composite rises. The interfacial accumulation of electrolytes provides an important contribution to the density enhancement. The study will be valuable for the dispersion and application of graphene nanomaterials.
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Affiliation(s)
- Shuyan Liu
- State Key Laboratory of Material-Orientated Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology , Nanjing 210009, China
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7
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Interaction forces between silica surfaces in cationic surfactant solutions: An atomic force microscopy study. J Colloid Interface Sci 2013; 402:19-26. [DOI: 10.1016/j.jcis.2012.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 11/05/2012] [Indexed: 11/20/2022]
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8
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Totland C, Blokhus AM, Nerdal W. The nature of alcohol co-adsorption sites and their effects on surfactant aggregate structure on silica investigated by 2H and 13C NMR. RSC Adv 2013. [DOI: 10.1039/c3ra42495b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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9
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Li L, Du X, Lu Y, Yang Z. Study on the first-step adsorption of dodecyltrimethylammonium bromide solutions on silica wafer surfaces by ultramicroelectrode voltammetry. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.06.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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10
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Parida SK, Dash S, Patel S, Mishra BK. Adsorption of organic molecules on silica surface. Adv Colloid Interface Sci 2006; 121:77-110. [PMID: 16879799 DOI: 10.1016/j.cis.2006.05.028] [Citation(s) in RCA: 347] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2005] [Revised: 05/17/2006] [Accepted: 05/17/2006] [Indexed: 11/29/2022]
Abstract
The adsorption behaviour of various organic adsorbates on silica surface is reviewed. Most of the structural information on silica is obtained from IR spectral data and from the characteristics of water present at the silica surface. Silica surface is generally embedded with hydroxy groups and ethereal linkages, and hence considered to have a negative charged surface prone to adsorption of electron deficient species. Adsorption isotherms of the adsorbates delineate the nature of binding of the adsorbate with silica. Aromatic compounds are found to involve the pi-cloud in hydrogen bonding with silanol OH group during adsorption. Cationic and nonionic surfactants adsorb on silica surface involving hydrogen bonding. Sometimes, a polar part of the surfactants also contributes to the adsorption process. Styryl pyridinium dyes are found to anchor on silica surface in flat-on position. On modification of the silica by treating with alkali, the adsorption behaviour of cationic surfactant or polyethylene glycol changes due to change in the characteristics of silica or modified silica surface. In case of PEG-modified silica, adsolubilization of the adsorbate is observed. By using a modified adsorption equation, hemimicellization is proposed for these dyes. Adsorptions of some natural macromolecules like proteins and nucleic acids are investigated to study the hydrophobic and hydrophilic binding sites of silica. Artificial macromolecules like synthetic polymers are found to be adsorbed on silica surface due to the interaction of the multifunctional groups of the polymers with silanols. Preferential adsorption of polar adsorbates is observed in case of adsorbate mixtures. When surfactant mixtures are considered to study competitive adsorption on silica surface, critical micelle concentration of individual surfactant also contributes to the adsorption isotherm. The structural study of adsorbed surface and the thermodynamics of adsorption are given some importance in this review.
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Affiliation(s)
- Sudam K Parida
- Centre of Studies in Surface Science and Technology, Department of Chemistry, Jyoti Vihar, 768 019, Orissa, India
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Blom A, Warr GG. Structure and composition of cationic-nonionic surfactant mixed adsorbed layers on mica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:6787-95. [PMID: 16863223 DOI: 10.1021/la0604477] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The composition and morphology of mixed adsorbed layers comprising one of several poly(oxyethylene) alkyl ether nonionic surfactants, C(i)E(j), and two cationic surfactants-dodecyltrimethylammonium bromide (DTAB) and tetradecyltriethylammonium bromide (TTeAB)-at the mica/solution interface have been studied using depletion adsorption and atomic force microscopy. The nonionic surfactants do not themselves adsorb onto mica, but can coadsorb with a cationic surfactant. The extent of their hydrophobic association with the adsorbed cationic surfactant depends on alkyl chain length, while the adsorbed layer morphologies are sensitive to the number of ethoxy groups. Nonionic surfactants with headgroups containing less than eight ethylene oxide units decrease the adsorbed aggregate curvature, gradually transforming globular TTeAB or cylindrical DTAB adsorbed aggregates into a rod, mesh, or bilayer structure. Those with larger headgroups favor globular aggregates. The mechanism by which the nonionic surfactant modifies the adsorbed morphology is the formation of defects in the form of cylinder end-caps or branch-points, leading to adsorbed layer compositions that differ from ideal mixing predictions. All mixed adsorbed films become saturated with the nonionic component when the capacity of the aqueous side of the adsorbed layer is reached.
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Affiliation(s)
- Annabelle Blom
- School of Chemistry, University of Sydney, NSW 2006 Australia
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12
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Theander K, Pugh RJ, Rutland MW. Friction force measurements relevant to de-inking by means of atomic force microscope. J Colloid Interface Sci 2005; 291:361-8. [PMID: 15961095 DOI: 10.1016/j.jcis.2005.05.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 05/12/2005] [Accepted: 05/13/2005] [Indexed: 11/28/2022]
Abstract
In the pulping step of the de-inking process, the ink detaches from the fibers due to shear and physical chemical interaction. In order to get a better understanding of the forces involved between cellulose and ink, the atomic force microscope and the colloidal probe technique have been used in the presence of a model chemical dispersant (hexa-ethyleneglycol mono n-dodecyl ether, C12E6). A cellulose bead was used as the colloidal probe and three different lower surfaces have been used, an alkyd resin, mica and a cellulose sphere. The normal and lateral forces have been measured at a range of nonionic concentrations. It was found that the lateral sliding friction forces deceased with increasing surfactant concentration for both the alkyd resin and mica while no differences were observed for the cellulose surface. In addition, only a very small change in normal force could be detected for the alkyd surface as the concentration changed.
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Affiliation(s)
- Katarina Theander
- Department of Chemistry, Surface Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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