1
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Teshima H, Fukunaga T, Li QY, Takahashi K. Precursor-film-driven ultra-early depinning of the three-phase contact line. J Colloid Interface Sci 2024; 678:1230-1238. [PMID: 39342868 DOI: 10.1016/j.jcis.2024.09.170] [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: 05/30/2024] [Revised: 09/14/2024] [Accepted: 09/18/2024] [Indexed: 10/01/2024]
Abstract
HYPOTHESIS Despite its importance in colloid and interface science, contact line pinning remains poorly understood, especially in the presence of a precursor film. We hypothesized that this is due to a lack of an experimental method capable of directly observing their physics at the nanoscale. METHODS Using coherence scanning interferometry, we visualized the three-dimensional behavior of contact lines with a precursor film near a nanogroove structure composed of flat terrace surfaces and steps with an inclination angle of 30° while achieving nanoscale vertical resolution. FINDINGS We found that even when the contact line is pinned at the edge of the step, the precursor film is not and advances beyond the edge. Furthermore, we discovered that the precursor film has two distinct effects on contact line motion. Specifically, the precursor film facilitates depinning when the contact line descends the step - a contact angle change was 0.9°, only 3.0% of the value predicted by a classical theory of contact angle at a solid edge. This ultra-early depinning is attributed to the formation of a new liquid film past the edge, driven by the progression of the precursor film that overcomes the pinning effect. In contrast, when the contact line ascends the step, the precursor film acts as a resistance to movement due to steric interaction.
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Affiliation(s)
- Hideaki Teshima
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan; International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan.
| | - Takanobu Fukunaga
- Technical Division, School of Engineering, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
| | - Qin-Yi Li
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan; International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
| | - Koji Takahashi
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan; International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
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2
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Rawat S, Trius Béjar J, Wang A. Characterization of Optical, Thermal, and Viscoelastic Properties of Pollenkitt in Angiosperm Pollen Using In-Line Digital Holographic Microscopy. ACS APPLIED BIO MATERIALS 2024; 7:4029-4038. [PMID: 38756048 DOI: 10.1021/acsabm.4c00367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Pollen grains are remarkable material composites, with various organelles in their fragile interior protected by a strong shell made of sporopollenin. The outermost layer of angiosperm pollen grains contains a lipid-rich substance called pollenkitt, which is a natural bioadhesive that helps preserve structural integrity when the pollen grain is exposed to external environmental stresses. In addition, its viscous nature enables it to adhere to various floral and insect surfaces, facilitating the pollination process. To examine the physicochemical properties of aqueous pollenkitt droplets, we used in-line digital holographic microscopy to capture light scattering from individual pollenkitt particles. Comparison of pollenkitt holograms to those modeled using the Lorenz-Mie theory enables investigations into the minute variations in the refractive index and size resulting from changes in local temperature and pollen aging.
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Affiliation(s)
- Siddharth Rawat
- School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
- School of Physics, UNSW Sydney, Sydney, New South Wales 2052, Australia
- Australian Centre for Astrobiology, UNSW Sydney, Sydney, New South Wales 2052, Australia
- ARC CoE in Synthetic Biology, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Juan Trius Béjar
- Departament de Física, Universitat Politècnica de Catalunya, Barcelona 08034, Spain
| | - Anna Wang
- School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
- Australian Centre for Astrobiology, UNSW Sydney, Sydney, New South Wales 2052, Australia
- ARC CoE in Synthetic Biology, UNSW Sydney, Sydney, New South Wales 2052, Australia
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3
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Brault D, Olivier T, Faure N, Dixneuf S, Kolytcheff C, Charmette E, Soulez F, Fournier C. Multispectral in-line hologram reconstruction with aberration compensation applied to Gram-stained bacteria microscopy. Sci Rep 2023; 13:14437. [PMID: 37660181 PMCID: PMC10475072 DOI: 10.1038/s41598-023-41079-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/21/2023] [Indexed: 09/04/2023] Open
Abstract
In multispectral digital in-line holographic microscopy (DIHM), aberrations of the optical system affect the repeatability of the reconstruction of transmittance, phase and morphology of the objects of interest. Here we address this issue first by model fitting calibration using transparent beads inserted in the sample. This step estimates the aberrations of the optical system as a function of the lateral position in the field of view and at each wavelength. Second, we use a regularized inverse problem approach (IPA) to reconstruct the transmittance and phase of objects of interest. Our method accounts for shift-variant chromatic and geometrical aberrations in the forward model. The multi-wavelength holograms are jointly reconstructed by favouring the colocalization of the object edges. The method is applied to the case of bacteria imaging in Gram-stained blood smears. It shows our methodology evaluates aberrations with good repeatability. This improves the repeatability of the reconstructions and delivers more contrasted spectral signatures in transmittance and phase, which could benefit applications of microscopy, such as the analysis and classification of stained bacteria.
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Affiliation(s)
- Dylan Brault
- Université Jean Monnet Saint-Etienne, CNRS, Institut d Optique Graduate School, Laboratoire Hubert Curien UMR 5516, 42023, Saint-Etienne, France
| | - Thomas Olivier
- Université Jean Monnet Saint-Etienne, CNRS, Institut d Optique Graduate School, Laboratoire Hubert Curien UMR 5516, 42023, Saint-Etienne, France
| | - Nicolas Faure
- bioMérieux, Centre Christophe Mérieux, 38024, Grenoble, France
| | - Sophie Dixneuf
- BIOASTER, Bioassays, Microsystems and Optical Engineering Unit, Lyon, France
| | | | | | - Ferréol Soulez
- Univ. de Lyon, Université Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR 5574, 69230, Saint-Genis-Laval, France
| | - Corinne Fournier
- Université Jean Monnet Saint-Etienne, CNRS, Institut d Optique Graduate School, Laboratoire Hubert Curien UMR 5516, 42023, Saint-Etienne, France.
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4
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Altman LE, Grier DG. Machine learning enables precise holographic characterization of colloidal materials in real time. SOFT MATTER 2023; 19:3002-3014. [PMID: 37017639 DOI: 10.1039/d2sm01283a] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Holographic particle characterization uses in-line holographic video microscopy to track and characterize individual colloidal particles dispersed in their native fluid media. Applications range from fundamental research in statistical physics to product development in biopharmaceuticals and medical diagnostic testing. The information encoded in a hologram can be extracted by fitting to a generative model based on the Lorenz-Mie theory of light scattering. Treating hologram analysis as a high-dimensional inverse problem has been exceptionally successful, with conventional optimization algorithms yielding nanometer precision for a typical particle's position and part-per-thousand precision for its size and index of refraction. Machine learning previously has been used to automate holographic particle characterization by detecting features of interest in multi-particle holograms and estimating the particles' positions and properties for subsequent refinement. This study presents an updated end-to-end neural-network solution called CATCH (Characterizing and Tracking Colloids Holographically) whose predictions are fast, precise, and accurate enough for many real-world high-throughput applications and can reliably bootstrap conventional optimization algorithms for the most demanding applications. The ability of CATCH to learn a representation of Lorenz-Mie theory that fits within a diminutive 200 kB hints at the possibility of developing a greatly simplified formulation of light scattering by small objects.
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Affiliation(s)
- Lauren E Altman
- Department of Physics and Center for Soft Matter Research, New York University, New York, NY 10003, USA.
| | - David G Grier
- Department of Physics and Center for Soft Matter Research, New York University, New York, NY 10003, USA.
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5
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Villa S, Larobina D, Stocco A, Blanc C, Villone MM, D'Avino G, Nobili M. Dynamics of prolate spheroids in the vicinity of an air-water interface. SOFT MATTER 2023; 19:2646-2653. [PMID: 36967649 DOI: 10.1039/d2sm01665f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In this article, we present the mobilities of prolate ellipsoidal micrometric particles close to an air-water interface measured by dual wave reflection interference microscopy. Particle's position and orientation with respect to the interface are simultaneously measured as a function of time. From the measured mean square displacement, five particle mobilities (3 translational and 2 rotational) and two translational-rotational cross-correlations are extracted. The fluid dynamics governing equations are solved by the finite element method to numerically evaluate the same mobilities, imposing either slip and no-slip boundary conditions to the flow at the air-water interface. The comparison between experiments and simulations reveals an agreement with no-slip boundary conditions prediction for the translation normal to the interface and the out-of-plane rotation, and with slip ones for parallel translations and in-plane rotation. We rationalize these evidences in the framework of surface incompressibility at the interface.
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Affiliation(s)
- Stefano Villa
- Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany.
| | - Domenico Larobina
- Institute of Polymers, Composites, and Biomaterials, National Research Council of Italy, Naples, 80055 Portici, Italy
| | - Antonio Stocco
- Institut Charles Sadron, CNRS UPR22, University of Strasbourg, Strasbourg, France
| | - Christophe Blanc
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
| | - Massimiliano M Villone
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Naples, Italy
| | - Gaetano D'Avino
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Naples, Italy
| | - Maurizio Nobili
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
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6
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Morgan SO, Muravitskaya A, Lowe C, Adawi AM, Bouillard JSG, Horozov TS, Stasiuk GJ, Buzza DMA. Using adsorption kinetics to assemble vertically aligned nanorods at liquid interfaces for metamaterial applications. Phys Chem Chem Phys 2022; 24:11000-11013. [PMID: 35467675 DOI: 10.1039/d1cp05484h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vertically aligned monolayers of metallic nanorods have a wide range of applications as metamaterials or in surface enhanced Raman spectroscopy. However the fabrication of such structures using current top-down methods or through assembly on solid substrates is either difficult to scale up or have limited possibilities for further modification after assembly. The aim of this paper is to use the adsorption kinetics of cylindrical nanorods at a liquid interface as a novel route for assembling vertically aligned nanorod arrays that overcomes these problems. Specifically, we model the adsorption kinetics of the particle using Langevin dynamics coupled to a finite element model, accurately capturing the deformation of the liquid meniscus and particle friction coefficients during adsorption. We find that the final orientation of the cylindrical nanorod is determined by their initial attack angle when they contact the liquid interface, and that the range of attack angles leading to the end-on state is maximised when nanorods approach the liquid interface from the bulk phase that is more energetically favorable. In the absence of an external field, only a fraction of adsorbing nanorods end up in the end-on state (≲40% even for nanorods approaching from the energetically favourable phase). However, by pre-aligning the metallic nanorods with experimentally achievable electric fields, this fraction can be effectively increased to 100%. Using nanophotonic calculations, we also demonstrate that the resultant vertically aligned structures can be used as epsilon-near-zero and hyperbolic metamaterials. Our kinetic assembly method is applicable to nanorods with a range of diameters, aspect ratios and materials and therefore represents a versatile, low-cost and powerful platform for fabricating vertically aligned nanorods for metamaterial applications.
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Affiliation(s)
- S O Morgan
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, UK.
| | - A Muravitskaya
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, UK.
| | - C Lowe
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, UK.
| | - A M Adawi
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, UK.
| | - J-S G Bouillard
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, UK.
| | - T S Horozov
- Department of Chemistry & Biochemistry, University of Hull, Hull HU6 7RX, UK
| | - G J Stasiuk
- Imaging Chemistry & Biology, King's College London, Strand, London WC2R 2LS, UK
| | - D M A Buzza
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, UK.
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7
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Attard MRG, Bowen J, Corado R, Hall LS, Dorey RA, Portugal SJ. Ecological drivers of eggshell wettability in birds. J R Soc Interface 2021; 18:20210488. [PMID: 34637642 PMCID: PMC8510701 DOI: 10.1098/rsif.2021.0488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 09/13/2021] [Indexed: 01/22/2023] Open
Abstract
Complex and at times extreme environments have pushed many bird species to develop unique eggshell surface properties to protect the embryo from external threats. Because microbes are usually transmitted into eggs by moisture, some species have evolved hydrophobic shell surfaces that resist water absorption, while also regulating heat loss and the exchange of gases. Here, we investigate the relationship between the wettability of eggshells from 441 bird species and their life-history traits. We measured the initial contact angle between sessile water droplets and the shell surface, and how far the droplet spread. Using phylogenetic comparative methods, we show that body mass, annual temperature and eggshell maculation primarily explained variance in water contact angle across eggshells. Species nesting in warm climates were more likely to exhibit highly hydrophobic eggshells than those nesting in cold climates, potentially to reduce microbial colonization. In non-passerines, immaculate eggs were found to have more hydrophobic surfaces than maculate eggshells. Droplets spread more quickly on eggshells incubated in open nests compared to domed nests, likely to decrease heat transfer from the egg. Here, we identify clear adaptations of eggshell wettability across a diverse range of nesting environments, driven by the need to retain heat and prevent microbial adhesion.
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Affiliation(s)
- Marie R. G. Attard
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
- School of Engineering and Innovation, Open University, Milton Keynes MK7 6AA, UK
| | - James Bowen
- School of Engineering and Innovation, Open University, Milton Keynes MK7 6AA, UK
| | - René Corado
- Western Foundation of Vertebrate Zoology, Camarillo, CA 93012-8506, USA
| | - Linnea S. Hall
- Western Foundation of Vertebrate Zoology, Camarillo, CA 93012-8506, USA
| | - Robert A. Dorey
- Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Steven J. Portugal
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
- The Natural History Museum, Tring, Herts HP23 6AP, UK
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8
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Morgan SO, Fox J, Lowe C, Adawi AM, Bouillard JSG, Stasiuk GJ, Horozov TS, Buzza DMA. Adsorption trajectories of nonspherical particles at liquid interfaces. Phys Rev E 2021; 103:042604. [PMID: 34005913 DOI: 10.1103/physreve.103.042604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 03/22/2021] [Indexed: 11/07/2022]
Abstract
The adsorption of colloidal particles at liquid interfaces is of great importance scientifically and industrially, but the dynamics of the adsorption process is still poorly understood. In this paper we use a Langevin model to study the adsorption dynamics of ellipsoidal colloids at a liquid interface. Interfacial deformations are included by coupling our Langevin dynamics to a finite element model while transient contact line pinning due to nanoscale defects on the particle surface is encoded into our model by renormalizing particle friction coefficients and using dynamic contact angles relevant to the adsorption timescale. Our simple model reproduces the monotonic variation of particle orientation with time that is observed experimentally and is also able to quantitatively model the adsorption dynamics for some experimental ellipsoidal systems but not others. However, even for the latter case, our model accurately captures the adsorption trajectory (i.e., particle orientation versus height) of the particles. Our study clarifies the subtle interplay between capillary, viscous, and contact line forces in determining the wetting dynamics of micron-scale objects, allowing us to design more efficient assembly processes for complex particles at liquid interfaces.
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Affiliation(s)
- S O Morgan
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, United Kingdom
| | - J Fox
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, United Kingdom.,School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - C Lowe
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, United Kingdom
| | - A M Adawi
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, United Kingdom
| | - J-S G Bouillard
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, United Kingdom
| | - G J Stasiuk
- Imaging Chemistry & Biology, King's College London, Strand, London WC2R 2LS, United Kingdom
| | - T S Horozov
- Department of Chemistry & Biochemistry, University of Hull, Hull HU6 7RX, United Kingdom
| | - D M A Buzza
- Department of Physics & Mathematics, University of Hull, Hull HU6 7RX, United Kingdom
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9
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Hunter SJ, Armes SP. Pickering Emulsifiers Based on Block Copolymer Nanoparticles Prepared by Polymerization-Induced Self-Assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15463-15484. [PMID: 33325720 PMCID: PMC7884006 DOI: 10.1021/acs.langmuir.0c02595] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/27/2020] [Indexed: 05/28/2023]
Abstract
Block copolymer nanoparticles prepared via polymerization-induced self-assembly (PISA) represent an emerging class of organic Pickering emulsifiers. Such nanoparticles are readily prepared by chain-extending a soluble homopolymer precursor using a carefully selected second monomer that forms an insoluble block in the chosen solvent. As the second block grows, it undergoes phase separation that drives in situ self-assembly to form sterically stabilized nanoparticles. Conducting such PISA syntheses in aqueous solution leads to hydrophilic nanoparticles that enable the formation of oil-in-water emulsions. Alternatively, hydrophobic nanoparticles can be prepared in non-polar media (e.g., n-alkanes), which enables water-in-oil emulsions to be produced. In this review, the specific advantages of using PISA to prepare such bespoke Pickering emulsifiers are highlighted, which include fine control over particle size, copolymer morphology, and surface wettability. This has enabled various fundamental scientific questions regarding Pickering emulsions to be addressed. Moreover, block copolymer nanoparticles can be used to prepare Pickering emulsions over various length scales, with mean droplet diameters ranging from millimeters to less than 200 nm.
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Affiliation(s)
- Saul J. Hunter
- Department of Chemistry,
Dainton Building, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| | - Steven P. Armes
- Department of Chemistry,
Dainton Building, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
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10
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Ji X, Wang X, Zhang Y, Zang D. Interfacial viscoelasticity and jamming of colloidal particles at fluid-fluid interfaces: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2020; 83:126601. [PMID: 32998118 DOI: 10.1088/1361-6633/abbcd8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Colloidal particles can be adsorbed at fluid-fluid interfaces, a phenomenon frequently observed in particle-stabilized foams, Pickering emulsions, and bijels. Particles adsorbed at interfaces exhibit unique physical and chemical behaviors, which affect the mechanical properties of the interface. Therefore, interfacial colloidal particles are of interest in terms of both fundamental and applied research. In this paper, we review studies on the adsorption of colloidal particles at fluid-fluid interfaces, from both thermodynamic and mechanical points of view, and discuss the differences as compared with surfactants and polymers. The unique particle interactions induced by the interfaces as well as the particle dynamics including lateral diffusion and contact line relaxation will be presented. We focus on the rearrangement of the particles and the resultant interfacial viscoelasticity. Particular emphasis will be given to the effects of particle shape, size, and surface hydrophobicity on the interfacial particle assembly and the mechanical properties of the obtained particle layer. We will also summarize recent advances in interfacial jamming behavior caused by adsorption of particles at interfaces. The buckling and cracking behavior of particle layers will be discussed from a mechanical perspective. Finally, we suggest several potential directions for future research in this area.
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Affiliation(s)
- Xiaoliang Ji
- Soft Matter & Complex Fluids Group, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710129, People's Republic of China
| | - Xiaolu Wang
- Institute of Welding and Surface Engineering Technology, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100124, People's Republic of China
| | - Yongjian Zhang
- Shaanxi Key Laboratory of Surface Engineering and Remanufacturing, Xi'an University, Xi'an 710065, People's Republic of China
| | - Duyang Zang
- Soft Matter & Complex Fluids Group, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710129, People's Republic of China
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11
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Hu M, Hsu CP, Isa L. Particle Surface Roughness as a Design Tool for Colloidal Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11171-11182. [PMID: 32897078 DOI: 10.1021/acs.langmuir.0c02050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Control over the surface roughness of colloidal particles offers exciting opportunities to tailor the properties and the processing of a broad range of soft matter systems. Moreover, identifying surface roughness as a design parameter reveals the possibility to connect seemingly distinct phenomena and materials via the role played by roughness effects. In this feature article, we concisely review some approaches to synthesize and characterize rough colloidal particles, with a focus on model spherical colloids. We then discuss the impact that surface roughness has on both the high-shear rheology of dense suspensions and the stabilization of Pickering emulsions. Commenting on developments of our own research, we aim to offer an original perspective for a property-oriented development of colloidal particles that transcends classical divisions between materials and processes toward innovative solutions.
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Affiliation(s)
- Minghan Hu
- Department of Materials ETH Zurich, Laboratory for Soft Materials and Interfaces, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
| | - Chiao-Peng Hsu
- Department of Materials ETH Zurich, Laboratory for Soft Materials and Interfaces, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
| | - Lucio Isa
- Department of Materials ETH Zurich, Laboratory for Soft Materials and Interfaces, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
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12
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Wang D, Zhu YL, Zhao Y, Li CY, Mukhopadhyay A, Sun ZY, Koynov K, Butt HJ. Brownian Diffusion of Individual Janus Nanoparticles at Water/Oil Interfaces. ACS NANO 2020; 14:10095-10103. [PMID: 32662990 PMCID: PMC7458482 DOI: 10.1021/acsnano.0c03291] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Janus nanoparticles could exhibit a higher interfacial activity and adsorb stronger to fluid interfaces than homogeneous nanoparticles of similar sizes. However, little is known about the interfacial diffusion of Janus nanoparticles and how it compares to that of homogeneous ones. Here, we employed fluorescence correlation spectroscopy to study the lateral diffusion of ligand-grafted Janus nanoparticles adsorbed at water/oil interfaces. We found that the diffusion was significantly slower than that of homogeneous nanoparticles. We carried out dissipative particle dynamic simulations to study the mechanism of interfacial slowdown. Good agreement between experimental and simulation results has been obtained only provided that the flexibility of ligands grafted on the nanoparticle surface was taken into account. The polymeric ligands were deformed and oriented at an interface so that the effective radius of Janus nanoparticles is larger than the nominal one obtained by measuring the diffusion in bulk solution. These findings highlight further the critical importance of the ligands grafted on Janus nanoparticles for applications involving nanoparticle adsorption at an interface, such as oil recovery or two-dimensional self-assembly.
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Affiliation(s)
- Dapeng Wang
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - You-Liang Zhu
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
| | - Yuehua Zhao
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
| | - Christopher Y. Li
- Department
of Materials Science and Engineering, Drexel
University, Philadelphia, Pennsylvania 19104, United States
| | - Ashis Mukhopadhyay
- Department
of Physics, Wayne State University, Detroit, Michigan 48201, United States
| | - Zhao-Yan Sun
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
| | - Kaloian Koynov
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Hans-Jürgen Butt
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
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13
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Effect of roughness-regulated migration and distribution of particles on the structural evolution of flowing polymer blends. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124454] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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14
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Scherz LF, Schroyen B, Pepicelli M, Schlüter DA, Vermant J, Vlassopoulos D. Molecularly Designed Interfacial Viscoelasticity by Dendronized Polymers: From Flexible Macromolecules to Colloidal Objects. ACS NANO 2019; 13:14217-14229. [PMID: 31743645 DOI: 10.1021/acsnano.9b07142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The thermodynamic and rheological properties of densely packed dendronized polymers (DPs) at water-air interfaces were studied here for first- and fourth-generation DPs (PG1, PG4) with both small (Pn ≈ 50) and large (Pn ≈ 500) backbone degrees of polymerization. The excellent control over the structural characteristics of these polymers enabled us to investigate how the interfacial properties change as we go from thin, flexible macromolecules toward thicker molecular objects that display colloidal features. The effects of the dendron generation, affecting the persistence length, as well as the degree of polymerization and surface pressure on the formation of DP layers at the water-air interface were studied. Surface pressure measurements and interfacial rheology suggest the existence of significant attractive interactions between the molecules of the higher generation DPs. While all DPs featured reproducible Π-A diagrams, successive compression-expansion cycles and surface pressure relaxation experiments revealed differences in the stability of the formed films, which are consistent with the variations in shape persistence and interactions between the studied DPs. Atomic force microscopy after Langmuir-Blodgett transfer of the films displayed a nanostructuring that can be attributed to the increase in attractive forces with increasing polymer generation and anisotropy. The importance of such structures on the surface properties was probed by interfacial shear rheology, which validated the existence of strong albeit brittle structures for fourth-generation DPs. Ultimately, we demonstrate how in particular rod-like DPs can be used as robust foam stabilizers.
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Affiliation(s)
- Leon F Scherz
- Department of Materials , ETH Zürich , 8093 Zürich , Switzerland
| | - Bram Schroyen
- Department of Materials , ETH Zürich , 8093 Zürich , Switzerland
| | | | | | - Jan Vermant
- Department of Materials , ETH Zürich , 8093 Zürich , Switzerland
| | - Dimitris Vlassopoulos
- Institute of Electronic Structure and Laser , FORTH, 70013 Heraklion , Greece
- Department of Materials Science and Technology , University of Crete , 70013 Heraklion , Greece
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15
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Zanini M, Cingolani A, Hsu CP, Fernández-Rodríguez MÁ, Soligno G, Beltzung A, Caimi S, Mitrano D, Storti G, Isa L. Mechanical phase inversion of Pickering emulsions via metastable wetting of rough colloids. SOFT MATTER 2019; 15:7888-7900. [PMID: 31532443 DOI: 10.1039/c9sm01352k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The possibility to invert emulsions from oil-in-water to water-in-oil (or vice versa) in a closed system, i.e. without any formulation change, remains an open fundamental challenge with many opportunities for industrial applications. Here, we propose a mechanism that exploits particle surface roughness to induce metastable wetting and obtain mechanically-responsive Pickering emulsions. We postulate that the phase inversion is driven by an in situ switch of the particle wettability from metastable positions at the interface following the input of controlled mechanical energy. Oil-in-water emulsions can be prepared at low energy using mildly hydrophobic rough colloids, which are dispersed in water and weakly pinned at the interface, and switched to water-in-oil emulsions by a second emulsification at higher energy, which triggers the relaxation of the particle contact angle. The same principle is demonstrated for the complementary emulsions using mildly hydrophilic colloids initially dispersed in oil. Our experiments and simulations support that the delicate interplay between particle surface design during synthesis and the energy of the emulsification process can encode a kinetic pathway for the phase inversion. Both organic and inorganic nanoparticles can be used, allowing for the future implementation of our strategy in a broad range of smart industrial formulations.
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Affiliation(s)
- Michele Zanini
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Zürich, Switzerland.
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16
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Aloi A, Vilanova N, Isa L, de Jong AM, Voets IK. Super-resolution microscopy on single particles at fluid interfaces reveals their wetting properties and interfacial deformations. NANOSCALE 2019; 11:6654-6661. [PMID: 30896703 DOI: 10.1039/c8nr08633h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Solid particles adsorbed at fluid interfaces are crucial for the mechanical stability of Pickering emulsions. The key parameter which determines the kinetic and thermodynamic properties of these colloids is the particle contact angle, θ. Several methods have recently been developed to measure the contact angle of individual particles adsorbed at liquid-liquid interfaces, as morphological and chemical heterogeneities at the particle surface can significantly affect θ. However, none of these techniques enables the simultaneous visualization of the nanoparticles and the reconstruction of the fluid interface to which they are adsorbed, in situ. To tackle this challenge, we utilize a newly developed super-resolution microscopy method, called iPAINT, which exploits non-covalent and continuous labelling of interfaces with photo-activatable fluorescent probes. Herewith, we resolve with nanometer accuracy both the position of individual nanoparticles at a water-octanol interface and the location of the interface itself. First, we determine single particle contact angles for both hydrophobic and hydrophilic spherical colloids. These experiments reveal a non-negligible dependence of θ on particle size, from which we infer an effective line tension, τ. Next, we image elliptical particles at a water-decane interface, showing that the corresponding interfacial deformations can be clearly captured by iPAINT microscopy.
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Affiliation(s)
- A Aloi
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands. and Laboratory of Self-Organizing Soft Matter, Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands and Laboratory of Macromolecular and Organic Chemistry, Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands
| | - N Vilanova
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands. and Laboratory of Macromolecular and Organic Chemistry, Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands
| | - L Isa
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog Weg 5, 8093 Zürich, Switzerland
| | - A M de Jong
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands. and Laboratory of Molecular Biosensing, Department of Applied Physics, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands
| | - I K Voets
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands. and Laboratory of Self-Organizing Soft Matter, Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands and Laboratory of Macromolecular and Organic Chemistry, Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands and Laboratory of Physical Chemistry, Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands
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17
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Anjali TG, Basavaraj MG. Shape-Anisotropic Colloids at Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3-20. [PMID: 29986588 DOI: 10.1021/acs.langmuir.8b01139] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Research in the 1980s demonstrated the formation of monolayers of particles achieved by interfacial particle trapping as a model system for investigating colloids in two dimensions. Since then, microscopy visualization of two-dimensional particle monolayers and quantification of the microstructure have led to significant fundamental understanding of a number of phenomena such as crystallization, freezing and melting transitions, dislocation dynamics, aggregation kinetics, and others. On the application front, particles at curved interfaces, as often the case in particle-stabilized emulsions and foams, have received considerable attention in the last few decades. The growing interest in the search for novel particles and new strategies to effect emulsion stabilization stems from their application in several disciplines. Moreover, particle-stabilized Pickering emulsions and foams can also be used to derive a number of advanced functional materials. Compared to several accounts of research on spherical colloids at fluid-fluid interfaces, investigations of the behavior of shape-anisotropic particles at interfaces, albeit receiving considerable attention in recent years, are still in a nascent stage. The objective of this feature article is to highlight our recent work in this area. In particular, the adsorption of shape-anisotropic particles to interfaces, wetting behavior, interfacial self-assembly, the response of nonspherical-particle-coated interfaces to compression and shear, and their ability to stabilize emulsions are discussed.
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Affiliation(s)
- Thriveni G Anjali
- Polymer Engineering and Colloid Science (PECS) Laboratory, Department of Chemical Engineering , Indian Institute of Technology Madras , Chennai 600 036 , India
| | - Madivala G Basavaraj
- Polymer Engineering and Colloid Science (PECS) Laboratory, Department of Chemical Engineering , Indian Institute of Technology Madras , Chennai 600 036 , India
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18
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Newton B, Mohammed R, Davies GB, Botto L, Buzza DMA. Capillary Interaction and Self-Assembly of Tilted Magnetic Ellipsoidal Particles at Liquid Interfaces. ACS OMEGA 2018; 3:14962-14972. [PMID: 31458162 PMCID: PMC6644019 DOI: 10.1021/acsomega.8b01818] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/24/2018] [Indexed: 05/04/2023]
Abstract
Magnetic ellipsoidal particles adsorbed at a liquid interface provide exciting opportunities for creating switchable functional materials, where self-assembly can be switched on and off using an external field [Davies et al., Adv. Mater., 2014, 26, 6715]. In order to gain a deeper understanding of this novel system in the presence of an external field, we study the capillary interaction and self-assembly of tilted ellipsoids using analytical theory and finite element simulations. We derive an analytical expression for the dipolar capillary interaction between tilted ellipsoids in elliptical polar coordinates, which exhibits a 1/r 2 power law dependence in the far field (i.e., large particle separations r) and correctly captures the orientational dependence of the capillary interactions in the near field. Using this dipole potential and finite element simulations, we further analyze the energy landscape of particle clusters consisting of up to eight tilted ellipsoids in contact. For clusters of two particles, we find that the side-to-side configuration is stable, whereas the tip-to-tip configuration is unstable. However, for clusters of more than three particles, we find that circular loops of side-to-side particles become globally stable, whereas linear chains of side-to-side particles become metastable. Furthermore, the energy barrier for the linear-to-loop transition decreases with increasing particle number. Our results explain both thermodynamically and kinetically why tilted ellipsoids assemble side-to-side locally but have a strong tendency to form loops on larger length scales.
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Affiliation(s)
- Bethany
J. Newton
- Nano3
Group, School of Mathematics & Physical Sciences, University of Hull, Hull HU6 7RX, U.K.
| | - Rizwaan Mohammed
- Nano3
Group, School of Mathematics & Physical Sciences, University of Hull, Hull HU6 7RX, U.K.
- Clare
College, Trinity Lane, Cambridge CB2 1TL, U.K.
| | - Gary B. Davies
- Institute
for Computational Physics, Allmandring 3, 70569 Stuttgart, Germany
| | - Lorenzo Botto
- School
of Engineering and Materials Science, Queen
Mary, University of London, London E1 4NS, U.K.
| | - D. Martin A. Buzza
- Nano3
Group, School of Mathematics & Physical Sciences, University of Hull, Hull HU6 7RX, U.K.
- E-mail: (D.M.A.B.)
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19
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Yu K, Zhang H, Biggs S, Xu Z, Cayre OJ, Harbottle D. The rheology of polyvinylpyrrolidone-coated silica nanoparticles positioned at an air-aqueous interface. J Colloid Interface Sci 2018; 527:346-355. [DOI: 10.1016/j.jcis.2018.05.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 05/09/2018] [Accepted: 05/14/2018] [Indexed: 10/16/2022]
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20
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Coertjens S, De Dier R, Moldenaers P, Isa L, Vermant J. Adsorption of Ellipsoidal Particles at Liquid-Liquid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2689-2697. [PMID: 28241120 DOI: 10.1021/acs.langmuir.6b03534] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The adsorption of particles at liquid-liquid interfaces is of great scientific and technological importance. In particular, for nonspherical particles, the capillary forces that drive adsorption vary with position and orientation, and complex adsorption pathways have been predicted by simulations. On the basis of the latter, it has been suggested that the timescales of adsorption are determined by a balance between capillary and viscous forces. However, several recent experimental results point out the role of contact line pinning in the adsorption of particles to interfaces and even suggest that the adsorption dynamics and pathways are completely determined by the latter, with the timescales of adsorption being determined solely by particle characteristics. In the present work, the adsorption trajectories of model ellipsoidal particles are investigated experimentally using cryo-SEM and by monitoring the altitudinal orientation angle using high-speed confocal microscopy. By varying the viscosity and the viscosity jump across the interfaces, we specifically interrogate the role of viscous forces.
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Affiliation(s)
- Stijn Coertjens
- Department of Chemical Engineering, KU Leuven , B-3001 Leuven, Belgium
| | | | - Paula Moldenaers
- Department of Chemical Engineering, KU Leuven , B-3001 Leuven, Belgium
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