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Xu C, Zhang Y, Sharma V. Spatiotemporal mapping of nanotopography and thickness transitions of ultrathin foam films. SOFT MATTER 2024; 20:3719-3727. [PMID: 38654634 DOI: 10.1039/d4sm00048j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Freshly formed soap films, soap bubbles, or foam films display iridescent colors due to thin film interference that changes as squeeze flow drives drainage and a progressive decrease in film thickness. Ultrathin (thickness <100 nm) freestanding films of soft matter containing micelles, particles, polyelectrolyte-surfactant complexes, or other supramolecular structures or liquid crystalline phases display drainage via stratification. A fascinating array of thickness variations and transitions, including stepwise thinning and coexistence of thick-thin flat regions, arise in micellar foam films that undergo drainage via stratification. In this tutorial, we describe the IDIOM (interferometry digital imaging optical microscopy) protocols that combine the conventional interferometry principle with digital filtration and image analysis to obtain nanometer accuracy for thickness determination while having high spatial and temporal resolution. We provide fully executable image analysis codes and algorithms for the analysis of nanotopography and summarize some of the unique insights obtained for stratified micellar foam films.
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Affiliation(s)
- Chenxian Xu
- Department of Chemical Engineering, University of Illinois Chicago, Chicago, IL, USA.
| | - Yiran Zhang
- Department of Chemical Engineering, University of Illinois Chicago, Chicago, IL, USA.
| | - Vivek Sharma
- Department of Chemical Engineering, University of Illinois Chicago, Chicago, IL, USA.
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2
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Singletary T, Drazer G, Marschilok AC, Takeuchi ES, Takeuchi KJ, Colosqui CE. Kinetic trapping of nanoparticles by solvent-induced interactions. NANOSCALE 2024; 16:5374-5382. [PMID: 38375739 DOI: 10.1039/d3nr06469g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Theoretical analysis based on mean field theory indicates that solvent-induced interactions (i.e. structural forces due to the rearrangement of wetting solvent molecules) not considered in DLVO theory can induce the kinetic trapping of nanoparticles at finite nanoscale separations from a well-wetted surface, under a range of ubiquitous physicochemical conditions for inorganic nanoparticles of common materials (e.g., metal oxides) in water or simple molecular solvents. This work proposes a simple analytical model that is applicable to arbitrary materials and simple solvents to determine the conditions for direct particle-surface contact or kinetic trapping at finite separations, by using experimentally measurable properties (e.g., Hamaker constants, interfacial free energies, and nanoparticle size) as input parameters. Analytical predictions of the proposed model are verified by molecular dynamics simulations and numerical solution of the Smoluchowski diffusion equation.
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Affiliation(s)
- Troy Singletary
- Mechanical Engineering Department, Stony Brook University, Stony Brook, NY 11794, USA.
| | - German Drazer
- Mechanical and Aerospace Engineering Department, Rutgers University, NJ 08854, USA
| | - Amy C Marschilok
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA.
- Interdisciplinary Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
- The Institute of Energy: Sustainability, Environment, and Equity, Stony Brook University, NY 11794, USA
| | - Esther S Takeuchi
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA.
- Interdisciplinary Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
- The Institute of Energy: Sustainability, Environment, and Equity, Stony Brook University, NY 11794, USA
| | - Kenneth J Takeuchi
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA.
- Interdisciplinary Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
- The Institute of Energy: Sustainability, Environment, and Equity, Stony Brook University, NY 11794, USA
| | - Carlos E Colosqui
- Mechanical Engineering Department, Stony Brook University, Stony Brook, NY 11794, USA.
- The Institute of Energy: Sustainability, Environment, and Equity, Stony Brook University, NY 11794, USA
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3
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King JP, Dagastine RR, Berry JD, Tabor RF. Stratification and film ripping induced by structural forces in granular micellar thin films. J Colloid Interface Sci 2024; 657:25-36. [PMID: 38029526 DOI: 10.1016/j.jcis.2023.11.068] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/18/2023] [Accepted: 11/10/2023] [Indexed: 12/01/2023]
Abstract
HYPOTHESIS Interactions across incredibly thin layers of fluids, known as thin films, underpin many important processes involving colloids, such as wetting-dewetting phenomena. Often in these systems, thin films are composed of complex fluids that contain dispersed components, such as spherical micelles, giving rise to oscillatory structural forces due to preferential layering under confinement. Modelling of thin film dynamics involving Derjaguin-Landau-Verwey-Overbeek (DLVO) type forces has been widely reported using the Stokes-Reynolds-Young-Laplace (SRYL) model, and we hypothesize that this theory can be extended to a concentrated micellar system by including an oscillatory structural force term in the disjoining pressure. EXPERIMENTS We study the drainage behaviour of thin films comprising sodium dodecyl sulfate (SDS) micelles across a range of concentrations and interaction conditions between an air bubble and a mica disk using a custom-built dual-wave interferometry apparatus. FINDINGS Early-stage film behaviour is dominated by hydrodynamics, which can be well reproduced by the SRYL model. However, experimental profiles drain significantly faster than predicted, transitioning into a structural force dominated phase characterised by four types of film ripping instabilities that we term 'waving', 'ridging', 'webbing', and 'hole-sheeting'. These instabilities were mapped according to SDS concentration and approach velocity, providing insight into the interplay between structural forces and hydrodynamic conditions.
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Affiliation(s)
- Joshua P King
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia
| | - Raymond R Dagastine
- Department of Chemical and Biomolecular Engineering and the Particulate Fluids Processing Centre, University of Melbourne, Parkville, VIC 3010, Australia
| | - Joseph D Berry
- Department of Chemical and Biomolecular Engineering and the Particulate Fluids Processing Centre, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Rico F Tabor
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia.
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4
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Höllring K, Baer A, Vučemilović-Alagić N, Smith DM, Smith AS. Anisotropic molecular diffusion in confinement II: A model for structurally complex particles applied to transport in thin ionic liquid films. J Colloid Interface Sci 2024; 657:272-289. [PMID: 38043229 DOI: 10.1016/j.jcis.2023.11.137] [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: 07/25/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023]
Abstract
HYPOTHESIS Diffusion in confinement is an important fundamental problem with significant implications for applications of supported liquid phases. However, resolving the spatially dependent diffusion coefficient, parallel and perpendicular to interfaces, has been a standing issue and for objects of nanometric size, which structurally fluctuate on a similar time scale as they diffuse, no methodology has been established so far. We hypothesise that the complex, coupled dynamics can be captured and analysed by using a model built on the 2-dimensional Smoluchowski equation and systematic coarse-graining. METHODS AND SIMULATIONS For large, flexible species, a universal approach is offered that does not make any assumptions about the separation of time scales between translation and other degrees of freedom. The method is validated on Molecular Dynamics simulations of bulk systems of a family of ionic liquids with increasing cation sizes where internal degrees of freedom have little to major effects. FINDINGS After validation on bulk liquids, where we provide an interpretation of two diffusion constants for each species found experimentally, we clearly demonstrate the anisotropic nature of diffusion coefficients at interfaces. Spatial variations in the diffusivities relate to interface-induced structuring of the ionic liquids. Notably, the length scales in strongly confined ionic liquids vary consistently but differently at the solid-liquid and liquid-vapour interfaces.
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Affiliation(s)
- Kevin Höllring
- PULS Group, Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Cauerstraß e 3, 91058, Erlangen, Germany
| | - Andreas Baer
- PULS Group, Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Cauerstraß e 3, 91058, Erlangen, Germany
| | - Nataša Vučemilović-Alagić
- PULS Group, Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Cauerstraß e 3, 91058, Erlangen, Germany; Group of Computational Life Sciences, Department of Physical Chemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb, 10000, Croatia
| | - David M Smith
- Group of Computational Life Sciences, Department of Physical Chemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb, 10000, Croatia
| | - Ana-Sunčana Smith
- PULS Group, Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Cauerstraß e 3, 91058, Erlangen, Germany; Group of Computational Life Sciences, Department of Physical Chemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb, 10000, Croatia.
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5
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Ochoa C, Gao S, Xu C, Srivastava S, Sharma V. Foam film stratification, viscosity, and small-angle X-ray scattering of micellar SDS solutions over an extended concentration range (1< c/CMC < 75). SOFT MATTER 2024; 20:1922-1934. [PMID: 38323381 DOI: 10.1039/d3sm01069d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Ultrathin foam films (thickness, h < 100 nm) containing micelles undergo drainage via stratification manifested as coexisting thick-thin flat regions, nanoscopic non-flat topography, and the stepwise decrease in film thickness that yields a characteristic step-size. Most studies characterize the variation in step size and stratification kinetics in micellar foam films in a limited concentration range, c/CMC < 12.5 (c < 100 mM). Likewise, most scattering studies characterize micelle dimensions, intermicellar distance, and volume fraction in bulk aqueous SDS solutions in this limited concentration range. In this contribution, we show drainage via stratification can be observed for concentrations up to c/CMC < 75 (c < 600 mM). Understanding the stratification behavior of freely draining micellar films with sodium dodecyl sulfate (SDS) concentration varying in the range 10 mM ≤ cSDS ≤ 600 mM is essential for molecular engineering, consumer product formulations, and controlling foaming in industrial processes. Here, we visualize and analyze nanoscopic thickness variations and transitions in stratifying foam films using Interferometry Digital Imaging Optical Microscopy (IDIOM) protocols. We compare step size obtained from foam stratification to micelle dimension, micelle volume fraction, and intermicellar distance obtained from small angle X-ray scattering studies. Even though the volume fraction increases and approaches 25% at c = 600 mM, the solution viscosity only increases by a factor of four compared to the solvent, consistent with the findings from both stratification and scattering studies. These comparisons allow us to explore the effect of micelle size, morphology, and intermicellar interactions on supramolecular oscillatory structural disjoining pressure, which influences the stratification behavior of draining foam films containing micelles under confinement.
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Affiliation(s)
- Chrystian Ochoa
- Department of Chemical Engineering, University of Illinois Chicago, 929 W Taylor St, Chicago, IL 60607, USA.
| | - Shang Gao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Chenxian Xu
- Department of Chemical Engineering, University of Illinois Chicago, 929 W Taylor St, Chicago, IL 60607, USA.
| | - Samanvaya Srivastava
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Center for Biological Physics, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Institute for Carbon Management, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Vivek Sharma
- Department of Chemical Engineering, University of Illinois Chicago, 929 W Taylor St, Chicago, IL 60607, USA.
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6
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Zhang Y, Huang R, Iepure M, Merriman S, Min Y. Geocolloidal interactions and relaxation dynamics under nanoconfinement: Effects of salinity and particle concentration. J Colloid Interface Sci 2023; 656:200-213. [PMID: 37989053 DOI: 10.1016/j.jcis.2023.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/23/2023]
Abstract
HYPOTHESIS Energy-related contaminants are frequently associated with geocolloids that translocate in underground fissures with dimensions comparable with geocolloids. To assess the transport and impact of energy-related contaminants in geological systems, fundamental understandings of interfacial behaviors of nanoparticles under confinement is imperative. We hypothesize that the dynamic properties of geocolloids, as well as their dependence on aqueous medium conditions would deviate from bulk behaviors under nanoconfinement. EXPERIMENTS Force profiles and rheological properties of 50 nm silica nanoparticles in aqueous media confined between mica surfaces as a function of surface separation, particle concentrations, and salinity were measured utilizing the surface forces apparatus. FINDINGS Force profiles revealed the critical surface separation for nonlinear rheological behaviors coincides with the onset of exponential repulsion between mica surfaces. When salts were absent, the normal forces and viscosity values of colloidal suspensions resembled pure water. In contrast, with salts, the force profiles and corresponding critical length scales were found to be highly sensitive to the particle concentration and the degree of confinement. A Newtonian to shear-thinning transition was captured with increasing degrees of confinement. Our results show that the interplay among confinement, particle, and ionic concentrations can alter the interparticle forces and rheological responses of true nanosized-colloidal suspensions and thus their transport behaviors under nanoconfinement for the first time.
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Affiliation(s)
- Yuanzhong Zhang
- Department of Chemical and Environmental Engineering, University of California, Riverside 92521 CA, USA
| | - Rundong Huang
- Department of Chemical and Environmental Engineering, University of California, Riverside 92521 CA, USA
| | - Monica Iepure
- Department of Chemical and Environmental Engineering, University of California, Riverside 92521 CA, USA
| | - Stephen Merriman
- School of Polymer Science and Polymer Engineering, University of Akron, 44325 OH, USA
| | - Younjin Min
- Department of Chemical and Environmental Engineering, University of California, Riverside 92521 CA, USA; Material Science and Engineering Program, University of California, Riverside, 92521 CA, USA.
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7
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Cafolla C, Voïtchovsky K, Payam AF. Simultaneous quantification of Young's modulus and dispersion forces with nanoscale spatial resolution. NANOTECHNOLOGY 2023; 34:505714. [PMID: 37699380 DOI: 10.1088/1361-6528/acf8ce] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/11/2023] [Indexed: 09/14/2023]
Abstract
Many advances in polymers and layered materials rely on a precise understanding of the local interactions between adjacent molecular or atomic layers. Quantifying dispersion forces at the nanoscale is particularly challenging with existing methods often time consuming, destructive, relying on surface averaging or requiring bespoke equipment. Here, we present a non-invasive method able to quantify the local mechanical and dispersion properties of a given sample with nanometer lateral precision. The method, based on atomic force microscopy (AFM), uses the frequency shift of a vibrating AFM cantilever in combination with established contact mechanics models to simultaneously derive the Hamaker constant and the effective Young's modulus at a given sample location. The derived Hamaker constant and Young's modulus represent an average over a small (typically <100) number of molecules or atoms. The oscillation amplitude of the vibrating AFM probe is used to select the length-scale of the features to analyse, with small vibrations able to resolve the contribution of sub-nanometric defects and large ones exploring effectively homogeneous areas. The accuracy of the method is validated on a range of 2D materials in air and water as well as on polymer thin films. We also provide the first experimental measurements of the Hamaker constant of HBN, MoT2, WSe2and polymer films, verifying theoretical predictions and computer simulations. The simplicity and robustness of the method, implemented with a commercial AFM, may support a broad range of technological applications in the growing field of polymers and nanostructured materials where a fine control of the van der Waals interactions is crucial to tune their properties.
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Affiliation(s)
- Clodomiro Cafolla
- Physics Department, Durham University, Durham, DH1 3LE, United Kingdom
| | | | - Amir Farokh Payam
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), School of Engineering, Ulster University, United Kingdom
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8
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Zhao Y, Shibahara M, Fan X, Zhang W, Liu C, Li J. The formation mechanism of the precursor film in high temperature molten metal systems: insight into structural disjoining pressure. Phys Chem Chem Phys 2023; 25:23909-23922. [PMID: 37642504 DOI: 10.1039/d3cp02192k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
A precursor film is a unique microfluidic entity that arises at the liquid/solid interface. The formation mechanism of this entity in high-temperature systems is yet to be explained, mainly due to the limitations posed by the increased reaction at the solid/liquid interface. In this study, we investigate the formation process of the precursor film in high-temperature molten metal systems (Ag/Ni, Au/Ni, and Cu/Ni) using molecular dynamics simulations. The alloying energies for different alloying pairs were determined to extract the excess energy, which was found to be distributed from the interface to the upper liquid. The pattern of this energy distribution determines the shape of the near-surface liquid, including the precursor film. This relationship is further reflected by the structural disjoining pressure, which is the excess pressure exerted by the ordered microstructures within the wedge-shaped area of the droplet. Strong nonlinearity has been found in the structural disjoining pressure of Ag/Ni and Au/Ni systems, which is considered to be the main reason for the formation of the precursor film. The fluctuation of the dissolution rate is also reflected in the disjoining pressure, and the inhibition of dissolution on the precursor film formation is phenomenally clarified.
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Affiliation(s)
- Yuren Zhao
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116081, China.
| | - Masahiko Shibahara
- Department of Mechanical Engineering, Osaka University, Suita, 565-0871, Japan
| | - Xingyu Fan
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116081, China.
| | - Wenhe Zhang
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116081, China.
| | - Chong Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116081, China.
- Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian, China
| | - Jingmin Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116081, China.
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Gao S, Ochoa C, Sharma V, Srivastava S. Salt Weakens Intermicellar Interactions and Structuring in Bulk Solutions and Foam Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11003-11014. [PMID: 36044777 DOI: 10.1021/acs.langmuir.2c01592] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Drainage via stratification in micellar foam films formulated with ionic surfactants shows dramatic changes on salt addition: both the step size and the number of steps in their stepwise thinning diminish. As the stratification process is governed by supramolecular oscillatory structural forces that arise due to confinement-induced structuring of micelles, it is apparent that salt addition reduces the magnitude, periodicity, and decay length of the oscillatory forces. In this contribution, we characterize the changes in micellar size, shape, and interactions on salt addition in bulk solutions using small-angle X-ray scattering (SAXS) to understand and elucidate the influence of salt on stratification in micellar foam films and, more broadly, on the oscillatory structural forces. Adding salt leads to a significant reduction in long-range correlations between micelles and smaller intermicellar distances. These effects manifest as a weakening of the primary peak of the structure factor, ascertained from SAXS spectra, accompanied by its shift to higher wave vectors. Weakened long-range correlations diminish the magnitude and periodicity of the oscillatory disjoining pressure leading to smaller step sizes, fewer steps, and a rich nanoscopic topography, due to the influence of disjoining pressure on the deformable interfaces. The step sizes in stratifying thin films and intermicellar distances in bulk solutions present incongruous values, implying an imperfect analogy with studies on charged nanoparticles with matched and salt concentration-independent values of measured interparticle distances that equal the periodicity of force-distance curves. We anticipate that our findings are significant for multicomponent soft and biological matter containing self-assembled supramolecular structures wherein screened Coulomb interactions govern the self-assembly, interfacial adsorption, interactions, dynamics, and stability.
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Affiliation(s)
- Shang Gao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Chrystian Ochoa
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60608, United States
| | - Vivek Sharma
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60608, United States
| | - Samanvaya Srivastava
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Center for Biological Physics, University of California, Los Angeles, Los Angeles, California 90095, United States
- Institute for Carbon Management, University of California, Los Angeles, Los Angeles, California 90095, United States
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10
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Nanofluid Structural Forces Alter Solid Wetting, Enhancing Oil Recovery. COLLOIDS AND INTERFACES 2022. [DOI: 10.3390/colloids6020033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nanofluids have attracted significant research interest for their promising application in enhanced oil recovery. One striking feature leading to the outstanding efficiency of nanofluids in enhanced oil recovery is the structure of nanoparticles, which induces oscillatory structural forces in the confined space between fluid–fluid interfaces or air–liquid and liquid–solid interfaces. To promote the understanding of the oscillatory structural forces and their application in enhanced oil recovery, we reviewed the origin and theory of the oscillatory structural forces, factors affecting their magnitude, and the experimental techniques demonstrating their impacts on enhanced oil recovery. We also reviewed the methods, where the benefits of nanofluids in enhanced oil recovery provided by the oscillatory structural forces are directly manifested. The oscillatory structural forces promote the wetting and spreading of nanofluids on solid surfaces, which ultimately enhances the separation of oil from the reservoir. Some imbibition tests demonstrated as much as 50% increased oil recovery, compared to the cases where the oscillatory structural forces were absent.
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11
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Nikolov AD, Wasan DT, Wu P. Solvation forces versus the nano-colloidal structural forces under the film confinement: Layer to in-layer structural transition in wetting solids. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2021.101539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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12
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Klaassen A, Liu F, Mugele F, Siretanu I. Correlation between Electrostatic and Hydration Forces on Silica and Gibbsite Surfaces: An Atomic Force Microscopy Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:914-926. [PMID: 35025512 PMCID: PMC8793142 DOI: 10.1021/acs.langmuir.1c02077] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 12/29/2021] [Indexed: 06/14/2023]
Abstract
The balance between hydration and Derjaguin-Landau-Verwey-Overbeek (DLVO) forces at solid-liquid interfaces controls many processes, such as colloidal stability, wetting, electrochemistry, biomolecular self-assembly, and ion adsorption. Yet, the origin of molecular scale hydration forces and their relation to the surface charge density that controls the continuum scale electrostatic forces is poorly understood. We argue that these two types of forces are largely independent of each other. To support this hypothesis, we performed atomic force microscopy experiments using intermediate-sized tips that enable the simultaneous detection of DLVO and molecular scale oscillatory hydration forces at the interface between composite gibbsite:silica-aqueous electrolyte interfaces. We extract surface charge densities from forces measured at tip-sample separations of 1.5 nm and beyond using DLVO theory in combination with charge regulation boundary conditions for various pH values and salt concentrations. We simultaneously observe both colloidal scale DLVO forces and oscillatory hydration forces for an individual crystalline gibbsite particle and the underlying amorphous silica substrate for all fluid compositions investigated. While the diffuse layer charge varies with pH as expected, the oscillatory hydration forces are found to be largely independent of pH and salt concentration, supporting our hypothesis that both forces indeed have a very different origin. Oscillatory hydration forces are found to be distinctly more pronounced on gibbsite than on silica. We rationalize this observation based on the distribution of hydroxyl groups available for H bonding on the two distinct surfaces.
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Affiliation(s)
- Aram Klaassen
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Fei Liu
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Igor Siretanu
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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13
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Xu K, Liu Y. Studies of probe tip materials by atomic force microscopy: a review. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:1256-1267. [PMID: 36415853 PMCID: PMC9644057 DOI: 10.3762/bjnano.13.104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 10/27/2022] [Indexed: 05/09/2023]
Abstract
As a tool that can test insulators' surface morphology and properties, the performance index of atomic force microscope (AFM) probes is the most critical factor in determining the resolution of microscopy, and the performance of probes varies in various modes and application requirements. This paper reviews the latest research results in metal, carbon nanotube, and colloidal probes and reviews their related methods and techniques, analyses the advantages and disadvantages of the improved probes compared with ordinary probes by comparing the differences in spatial resolution, sensitivity, imaging, and other performance aspects, and finally provides an outlook on the future development of AFM probes. This paper promotes the development of AFM probes in the direction of new probes and further promotes the broader and deeper application of scanning probe microscope (SPM).
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Affiliation(s)
- Ke Xu
- School of Electrical & Control Engineering, Shenyang Jianzhu University, Shenyang 110168, China
| | - Yuzhe Liu
- School of Electrical & Control Engineering, Shenyang Jianzhu University, Shenyang 110168, China
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14
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Ochoa C, Xu C, Martínez Narváez CDV, Yang W, Zhang Y, Sharma V. Drainage via stratification and nanoscopic thickness transitions of aqueous sodium naphthenate foam films. SOFT MATTER 2021; 17:8915-8924. [PMID: 34545906 DOI: 10.1039/d1sm01169c] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Sodium naphthenates (NaNs), found in crude oils and oil sands process-affected water (OSPW), can act as surfactants and stabilize undesirable foams and emulsions. Despite the critical impact of soap-like NaNs on the formation, properties, and stability of petroleum and OSPW foams, there is a significant lack of studies that characterize foam film drainage, motivating this study. Here, we contrast the drainage of aqueous foam films formulated with NaN with foams containing sodium dodecyl sulfate (SDS), a well-studied surfactant system, in the relatively low concentration regime (c/CMC < 12.5). The foam films exhibit drainage via stratification, displaying step-wise thinning and coexisting thick-thin regions manifested as distinct shades of gray in reflected light microscopy due to thickness-dependent interference intensity. Using IDIOM (interferometry digital imaging optical microscopy) protocols that we developed, we analyze pixel-wise intensity to obtain thickness maps with high spatiotemporal resolution (thickness <1 nm, lateral ∼500 nm, time ∼10 ms). The analysis of interference intensity variations over time reveals that the aqueous foam films of both SDS and NaN possess an evolving, dynamic, and rich nanoscopic topography. The nanoscopic thickness transitions for stratifying SDS foam films are attributed to the role played by damped supramolecular oscillatory structural disjoining pressure contributed by the confinement-induced layering of spherical micelles. In comparison with SDS, we find smaller concentration-dependent step size and terminal film thickness values for NaN, implying weaker intermicellar interactions and oscillatory structural disjoining pressure with shorter decay length and periodicity.
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Affiliation(s)
- Chrystian Ochoa
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA.
| | - Chenxian Xu
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA.
| | | | - William Yang
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA.
| | - Yiran Zhang
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA.
| | - Vivek Sharma
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA.
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15
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Forces between interfaces in concentrated nanoparticle suspensions and polyelectrolyte solutions. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Kosior D, Gvaramia M, Scarratt LRJ, Maroni P, Trefalt G, Borkovec M. Thickness of the particle-free layer near charged interfaces in suspensions of like-charged nanoparticles. SOFT MATTER 2021; 17:6212-6224. [PMID: 34105586 PMCID: PMC8243649 DOI: 10.1039/d1sm00584g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
When a suspension of charged nanoparticles is in contact with a like-charged water-solid interface, next to this interface a particle-free layer is formed. The present study provides reliable measurements of the thickness of this particle-free layer with three different techniques, namely optical reflectivity, quartz crystal microbalance (QCM), and direct force measurements with atomic force microscopy (AFM). Suspensions of negatively charged nanoparticles of different size and type are investigated. When the measured layer thickness is normalized to the particle size, one finds that this normalized thickness shows universal inverse square root dependence on the particle volume fraction. This universal dependence can be also derived from Poisson-Boltzmann theory for highly asymmetric electrolytes, whereby one has to assume that the nanoparticles represent the multivalent coions.
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Affiliation(s)
- Dominik Kosior
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Manuchar Gvaramia
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Liam R J Scarratt
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Plinio Maroni
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Gregor Trefalt
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Michal Borkovec
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
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17
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Abstract
Ultrathin foam films containing supramolecular structures like micelles in bulk and adsorbed surfactant at the liquid-air interface undergo drainage via stratification. At a fixed surfactant concentration, the stepwise decrease in the average film thickness of a stratifying micellar film yields a characteristic step size that also describes the quantized thickness difference between coexisting thick-thin flat regions. Even though many published studies claim that step size equals intermicellar distance obtained using scattering from bulk solutions, we found no reports of a direct comparison between the two length scales. It is well established that step size is inversely proportional to the cubic root of surfactant concentration but cannot be estimated by adding micelle size to Debye length, as the latter is inversely proportional to the square root of surfactant concentration. In this contribution, we contrast the step size obtained from analysis of nanoscopic thickness variations and transitions in stratifying foam films using Interferometry Digital Imaging Optical Microscopy (IDIOM) protocols, that we developed, with the intermicellar distance obtained using small-angle X-ray scattering. We find that stratification driven by the confinement-induced layering of micelles within the liquid-air interfaces of a foam film provides a sensitive probe of non-DLVO (Derjaguin-Landau-Verwey-Overbeek) supramolecular oscillatory structural forces and micellar interactions.
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18
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Perez-Martinez CS, Groves TS, Perkin S. Controlling adhesion using AC electric fields across fluid films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:31LT02. [PMID: 34020441 DOI: 10.1088/1361-648x/ac03d3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/21/2021] [Indexed: 06/12/2023]
Abstract
We demonstrate reversible and switchable actuation using AC electric fields to bring two surfaces separated by a thin film of ionic fluid in and out of adhesive contact. Using a surface force balance we apply electric fields normal to a crossed-cylinder contact and measure directly the adhesive force and surface separation with sub-molecular resolution. Taking advantage of the oscillatory structural force acting between the surfaces across the fluid, which we show to be unaffected by the AC field, we pick between the distinct (quantized) adhesive states through precise tuning of the field. This proof-of-concept indicates exquisite control of surface interactions using an external field.
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Affiliation(s)
- Carla S Perez-Martinez
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Timothy S Groves
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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19
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Landman J, Schelling MPM, Tuinier R, Vis M. Repulsive and attractive depletion forces mediated by nonadsorbing polyelectrolytes in the Donnan limit. J Chem Phys 2021; 154:164904. [PMID: 33940853 DOI: 10.1063/5.0044749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In mixtures of colloids and nonadsorbing polyelectrolytes, a Donnan potential arises across the region between surfaces that are depleted of the polyelectrolyte and the rest of the system. This Donnan potential tends to shift the polyelectrolyte density profile toward the colloidal surface and leads to the local accumulation of polyelectrolytes. We derive a zero-field theory for the disjoining pressure between two parallel flat plates. The polyelectrolyte is allowed to enter the confined interplate region at the cost of a conformational free energy penalty. The resulting disjoining pressure shows a crossover to a repulsive regime when the interplate separation gets smaller than the size of the polyelectrolyte chain, followed by an attractive part. We find a quantitative match between the model and self-consistent field computations that take into account the full Poisson-Boltzmann electrostatics.
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Affiliation(s)
- Jasper Landman
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Max P M Schelling
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Remco Tuinier
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Mark Vis
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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20
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Xiang L, Zhang J, Gong L, Zeng H. Surface forces and interaction mechanisms of soft thin films under confinement: a short review. SOFT MATTER 2020; 16:6697-6719. [PMID: 32648881 DOI: 10.1039/d0sm00924e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Surface forces of soft thin films under confinement in fluids play an important role in diverse biological and technological applications, such as bio-adhesion, lubrication and micro- and nano-electromechanical systems. Understanding the involved interaction mechanisms underlying the adhesion behaviors and tribological performances (i.e., friction and lubrication) of various confined soft thin films is significant in the development of both fundamental science and practical technologies. In this review, the fundamentals of surface forces are briefly presented. The widely utilized force measurement techniques including surface forces apparatus (SFA), atomic force microscopy (AFM) and spacer layer interferometry tribometer techniques are introduced. The advances in the fundamental understanding of a wide range of adhesion and tribological phenomena have been reviewed, in terms of the intermolecular and surface interaction mechanisms involved. The influences of various factors such as confined film properties, experimental conditions (e.g., normal load, and sliding velocity) and environmental variables (e.g., salts, salinity, additives and pH) on the adhesion, friction or lubrication forces of confined soft thin films are presented. The correlation between adhesion hysteresis and friction/lubrication behaviors has been discussed. Some of the challenging issues remaining and future perspectives are also provided.
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Affiliation(s)
- Li Xiang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
| | - Jiawen Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
| | - Lu Gong
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
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