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Zheng J, Chen J, Jin Y, Wen Y, Mu Y, Wu C, Wang Y, Tong P, Li Z, Hou X, Tang J. Photochromism from wavelength-selective colloidal phase segregation. Nature 2023; 617:499-506. [PMID: 37198311 PMCID: PMC10191859 DOI: 10.1038/s41586-023-05873-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/21/2023] [Indexed: 05/19/2023]
Abstract
Phase segregation is ubiquitously observed in immiscible mixtures, such as oil and water, in which the mixing entropy is overcome by the segregation enthalpy1-3. In monodispersed colloidal systems, however, the colloidal-colloidal interactions are usually non-specific and short-ranged, which leads to negligible segregation enthalpy4. The recently developed photoactive colloidal particles show long-range phoretic interactions, which can be readily tuned with incident light, suggesting an ideal model for studying phase behaviour and structure evolution kinetics5,6. In this work, we design a simple spectral selective active colloidal system, in which TiO2 colloidal species were coded with spectral distinctive dyes to form a photochromic colloidal swarm. In this system, the particle-particle interactions can be programmed by combining incident light with various wavelengths and intensities to enable controllable colloidal gelation and segregation. Furthermore, by mixing the cyan, magenta and yellow colloids, a dynamic photochromic colloidal swarm is formulated. On illumination of coloured light, the colloidal swarm adapts the appearance of incident light due to layered phase segregation, presenting a facile approach towards coloured electronic paper and self-powered optical camouflage.
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Affiliation(s)
- Jing Zheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
- Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Jingyuan Chen
- Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yakang Jin
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
- School of Physics, University of Electronic Science and Technology of China, Chengdu, China
| | - Yan Wen
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Yijiang Mu
- Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Changjin Wu
- Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yufeng Wang
- Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Penger Tong
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Zhigang Li
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Xu Hou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Jiujiang Research Institute, College of Physical Science and Technology, Xiamen University, Xiamen, China
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, China
| | - Jinyao Tang
- Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China.
- State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Hong Kong, China.
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2
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Guzmán E, Martínez-Pedrero F, Calero C, Maestro A, Ortega F, Rubio RG. A broad perspective to particle-laden fluid interfaces systems: from chemically homogeneous particles to active colloids. Adv Colloid Interface Sci 2022; 302:102620. [PMID: 35259565 DOI: 10.1016/j.cis.2022.102620] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 01/12/2023]
Abstract
Particles adsorbed to fluid interfaces are ubiquitous in industry, nature or life. The wide range of properties arising from the assembly of particles at fluid interface has stimulated an intense research activity on shed light to the most fundamental physico-chemical aspects of these systems. These include the mechanisms driving the equilibration of the interfacial layers, trapping energy, specific inter-particle interactions and the response of the particle-laden interface to mechanical perturbations and flows. The understanding of the physico-chemistry of particle-laden interfaces becomes essential for taking advantage of the particle capacity to stabilize interfaces for the preparation of different dispersed systems (emulsions, foams or colloidosomes) and the fabrication of new reconfigurable interface-dominated devices. This review presents a detailed overview of the physico-chemical aspects that determine the behavior of particles trapped at fluid interfaces. This has been combined with some examples of real and potential applications of these systems in technological and industrial fields. It is expected that this information can provide a general perspective of the topic that can be exploited for researchers and technologist non-specialized in the study of particle-laden interfaces, or for experienced researcher seeking new questions to solve.
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Affiliation(s)
- Eduardo Guzmán
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain; Unidad de Materia Condensada, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII 1, 28040 Madrid, Spain.
| | - Fernando Martínez-Pedrero
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
| | - Carles Calero
- Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Avenida Diagonal 647, 08028 Barcelona, Spain; Institut de Nanociència i Nanotecnologia, IN2UB, Universitat de Barcelona, Avenida, Diagonal 647, 08028 Barcelona, Spain
| | - Armando Maestro
- Centro de Fı́sica de Materiales (CSIC, UPV/EHU)-Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain; IKERBASQUE-Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
| | - Francisco Ortega
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain; Unidad de Materia Condensada, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII 1, 28040 Madrid, Spain
| | - Ramón G Rubio
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain; Unidad de Materia Condensada, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII 1, 28040 Madrid, Spain.
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3
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Guzmán E, Abelenda-Núñez I, Maestro A, Ortega F, Santamaria A, Rubio RG. Particle-laden fluid/fluid interfaces: physico-chemical foundations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:333001. [PMID: 34102618 DOI: 10.1088/1361-648x/ac0938] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/08/2021] [Indexed: 06/12/2023]
Abstract
Particle-laden fluid/fluid interfaces are ubiquitous in academia and industry, which has fostered extensive research efforts trying to disentangle the physico-chemical bases underlying the trapping of particles to fluid/fluid interfaces as well as the properties of the obtained layers. The understanding of such aspects is essential for exploiting the ability of particles on the stabilization of fluid/fluid interface for the fabrication of novel interface-dominated devices, ranging from traditional Pickering emulsions to more advanced reconfigurable devices. This review tries to provide a general perspective of the physico-chemical aspects associated with the stabilization of interfaces by colloidal particles, mainly chemical isotropic spherical colloids. Furthermore, some aspects related to the exploitation of particle-laden fluid/fluid interfaces on the stabilization of emulsions and foams will be also highlighted. It is expected that this review can be used for researchers and technologist as an initial approach to the study of particle-laden fluid layers.
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Affiliation(s)
- Eduardo Guzmán
- Departamento de Química Física, Universidad Complutense de Madrid, Madrid, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid, Spain
| | - Irene Abelenda-Núñez
- Departamento de Química Física, Universidad Complutense de Madrid, Madrid, Spain
| | | | - Francisco Ortega
- Departamento de Química Física, Universidad Complutense de Madrid, Madrid, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid, Spain
| | - Andreas Santamaria
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid, Spain
- Institut Laue-Langevin, Grenoble, France
| | - Ramón G Rubio
- Departamento de Química Física, Universidad Complutense de Madrid, Madrid, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid, Spain
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4
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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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5
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Ravnik M, Everts JC. Topological-Defect-Induced Surface Charge Heterogeneities in Nematic Electrolytes. PHYSICAL REVIEW LETTERS 2020; 125:037801. [PMID: 32745396 DOI: 10.1103/physrevlett.125.037801] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
We show that topological defects in an ion-doped nematic liquid crystal can be used to manipulate the surface charge distribution on chemically homogeneous, charge-regulating external surfaces, using a minimal theoretical model. In particular, the location and type of the defect encodes the precise distribution of surface charges and the effect is enhanced when the liquid crystal is flexoelectric. We demonstrate the principle for patterned surfaces and charged colloidal spheres. More generally, our results indicate an interesting approach to control surface charges on external surfaces without changing the surface chemistry.
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Affiliation(s)
- Miha Ravnik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
- Department of Condensed Matter Physics, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Jeffrey C Everts
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
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6
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Mußotter M, Bier M, Dietrich S. Heterogeneous surface charge confining an electrolyte solution. J Chem Phys 2020; 152:234703. [PMID: 32571064 DOI: 10.1063/5.0006208] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The structure of dilute electrolyte solutions close to a surface carrying a spatially inhomogeneous surface charge distribution is investigated by means of classical density functional theory within the approach of fundamental measure theory. For electrolyte solutions, the influence of these inhomogeneities is particularly strong because the corresponding characteristic length scale is the Debye length, which is large compared to molecular sizes. Here, a fully three-dimensional investigation is performed, which accounts explicitly for the solvent particles, and thus provides insight into effects caused by ion-solvent coupling. The present study introduces a versatile framework to analyze a broad range of types of surface charge heterogeneities even beyond the linear response regime. This reveals a sensitive dependence of the number density profiles of the fluid components and of the electrostatic potential on the magnitude of the charge as well as on the details of the surface charge patterns at small scales.
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Affiliation(s)
- Maximilian Mußotter
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Markus Bier
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - S Dietrich
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
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7
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Cuetos A, Morillo N, Martı Nez Haya B. Coadsorption of Counterionic Colloids at Fluid Interfaces: A Coarse-Grained Simulation Study of Gibbs Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2877-2885. [PMID: 32118442 DOI: 10.1021/acs.langmuir.9b03886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Monolayers of oppositely charged colloids form versatile self-organizing substrates, with a recognized potential to tailor functional interfaces. In this study, a coarse-grained Monte Carlo simulation approach is laid out to assess the structural properties of Gibbs monolayers, in which one of the counterionic species is partially soluble. It is shown that the composition of this type of monolayer varies in a nontrivial way with surface coverage, as a result of a subtle competition between steric and attractive forces. In the regime of weak electrostatic interactions, the monolayer is depleted of soluble colloids as the surface coverage is increased. At sufficiently strong interactions, the incorporation of soluble colloids is favored at high surface coverage, leading to a re-entrant-type behavior in the expansion/compression isotherms. Strong electrostatic interactions also favor the clustering of the colloids, leading to a range of aggregated configurations, qualitatively resembling those obtained in previous experimental studies. At sufficiently high surface coverage, the clusters collapse into a gel-like percolated mesoscopic structure and eventually into a square crystal lattice configuration. Such interfacial structures are in good agreement with the ones observed in the few experimental investigations available for these systems, showing that the simple methodology introduced in this study provides a valuable predictive framework to anticipate the landscape of interfacial structures that may be produced with oppositely charged colloids, through the modulation of pair interactions and thermodynamical conditions.
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Affiliation(s)
- Alejandro Cuetos
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Neftali Morillo
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Bruno Martı Nez Haya
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville, Spain
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8
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Wang A, Zwanikken JW, Kaz DM, McGorty R, Goldfain AM, Rogers WB, Manoharan VN. Before the breach: Interactions between colloidal particles and liquid interfaces at nanoscale separations. Phys Rev E 2019; 100:042605. [PMID: 31771009 DOI: 10.1103/physreve.100.042605] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Indexed: 06/10/2023]
Abstract
Particles bound to fluid-fluid interfaces are widely used to study self-assembly and to make materials such as Pickering emulsions. In both contexts, the lateral interactions between such particles have been studied extensively. However, much less is known about the normal interactions between a particle and the interface prior to contact. We use digital holographic microscopy to measure the dynamics of individual micrometer-size colloidal particles as they approach an interface between an aqueous phase and oil. Our measurements show that the interaction between the particle and interface changes nonmonotonically as a function of salt concentration, from repulsive at 1 mM to attractive at tens of mM to negligible at 100 mM and attractive again above 200 mM. In the attractive regimes, the particles can bind to the interface at nanometer-scale separation without breaching it. Classical Derjaguin-Landau-Verwey-Overbeek theory does not explain these observations. However, a theory that accounts for nonlinear screening and correlations between the ions does predict the nonmonotonic dependence on salt concentration and produces trajectories that agree with experimental data. We further show that the normal interactions determine the lateral interactions between particles that are bound to the interface. Because the interactions we observe occur at salt concentrations used to make Pickering emulsions and other particle-laden interfaces, our results suggest that particle arrangements at the interface are likely out of equilibrium on experimental timescales.
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Affiliation(s)
- Anna Wang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- School of Chemistry, UNSW Sydney, New South Wales 2052, Australia
| | - Jos W Zwanikken
- Department of Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA
| | - David M Kaz
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Ryan McGorty
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, USA
| | - Aaron M Goldfain
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - W Benjamin Rogers
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02453, USA
| | - Vinothan N Manoharan
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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9
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Mußotter M, Bier M, Dietrich S. Electrolyte solutions at heterogeneously charged substrates. SOFT MATTER 2018; 14:4126-4140. [PMID: 29693687 DOI: 10.1039/c8sm00497h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The influence of a chemically or electrically heterogeneous distribution of interaction sites at a planar substrate on the number density of an adjacent fluid is studied by means of classical density functional theory (DFT). In the case of electrolyte solutions the effect of this heterogeneity is particularly long ranged, because the corresponding relevant length scale is set by the Debye length which is large compared to molecular sizes. The DFT used here takes the solvent particles explicitly into account and thus captures phenomena, inter alia, due to ion-solvent coupling. The present approach provides closed analytic expressions describing the influence of chemically and electrically nonuniform walls. The analysis of isolated δ-like interactions, isolated interaction patches, and hexagonal periodic distributions of interaction sites reveals a sensitive dependence of the fluid density profiles on the type of the interaction, as well as on the size and the lateral distribution of the interaction sites.
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Affiliation(s)
- Maximilian Mußotter
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany.
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10
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Zanini M, Marschelke C, Anachkov SE, Marini E, Synytska A, Isa L. Universal emulsion stabilization from the arrested adsorption of rough particles at liquid-liquid interfaces. Nat Commun 2017; 8:15701. [PMID: 28589932 PMCID: PMC5467241 DOI: 10.1038/ncomms15701] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/21/2017] [Indexed: 11/09/2022] Open
Abstract
Surface heterogeneities, including roughness, significantly affect the adsorption, motion and interactions of particles at fluid interfaces. However, a systematic experimental study, linking surface roughness to particle wettability at a microscopic level, is currently missing. Here we synthesize a library of all-silica microparticles with uniform surface chemistry, but tuneable surface roughness and study their spontaneous adsorption at oil-water interfaces. We demonstrate that surface roughness strongly pins the particles' contact lines and arrests their adsorption in long-lived metastable positions, and we directly measure the roughness-induced interface deformations around isolated particles. Pinning imparts tremendous contact angle hysteresis, which can practically invert the particle wettability for sufficient roughness, irrespective of their chemical nature. As a unique consequence, the same rough particles stabilize both water-in-oil and oil-in-water emulsions depending on the phase they are initially dispersed in. These results both shed light on fundamental phenomena concerning particle adsorption at fluid interfaces and indicate future design rules for particle-based emulsifiers.
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Affiliation(s)
- Michele Zanini
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog Weg 5, 8093 Zürich, Switzerland
| | - Claudia Marschelke
- Department of Polymer Interfaces, Leibniz Institute of Polymer Research, Hohe Strasse 6, D-01069 Dresden, Germany
| | - Svetoslav E. Anachkov
- Department of Chemical and Pharmaceutical Engineering, Faculty of Chemistry and Pharmacy, Sofia University, 1 James Bourchier Avenue, 1164 Sofia, Bulgaria
| | - Emanuele Marini
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog Weg 5, 8093 Zürich, Switzerland
| | - Alla Synytska
- Department of Polymer Interfaces, Leibniz Institute of Polymer Research, Hohe Strasse 6, D-01069 Dresden, Germany
| | - Lucio Isa
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog Weg 5, 8093 Zürich, Switzerland
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11
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Zhang H, Yu K, Cayre OJ, Harbottle D. Interfacial Particle Dynamics: One and Two Step Yielding in Colloidal Glass. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:13472-13481. [PMID: 27993029 DOI: 10.1021/acs.langmuir.6b03586] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The yielding behavior of silica nanoparticles partitioned at an air-aqueous interface is reported. Linear viscoelasticity of the particle-laden interface can be retrieved via a time-dependent and electrolyte-dependent superposition, and the applicability of the "soft glassy rheology" (SGR) model is confirmed. With increasing electrolyte concentration (φelect) in the aqueous subphase, a nonergodic state is achieved with particle dynamics arrested first from attraction induced bonding bridges and then from the cage effect of particle jamming, manifesting in a two-step yielding process under large amplitude oscillation strain (LAOS). The Lissajous curves disclose a shear-induced in-cage particle redisplacement within oscillation cycles between the two yielding steps, exhibiting a "strain softening" transitioning to "strain stiffening" as the interparticle attraction increases. By varying φelect and the particle spreading concentration, φSiO2, a variety of phase transitions from fluid- to gel- and glass-like can be unified to construct a state diagram mapping the yielding behaviors from one-step to two-step before finally exhibiting one-step yielding at high φelect and φSiO2.
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Affiliation(s)
- Huagui Zhang
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Kai Yu
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Olivier J Cayre
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - David Harbottle
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
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12
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Wang A, McGorty R, Kaz DM, Manoharan VN. Contact-line pinning controls how quickly colloidal particles equilibrate with liquid interfaces. SOFT MATTER 2016; 12:8958-8967. [PMID: 27734049 DOI: 10.1039/c6sm01690a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Previous experiments have shown that spherical colloidal particles relax to equilibrium slowly after they adsorb to a liquid-liquid interface, despite the large interfacial energy gradient driving the adsorption. The slow relaxation has been explained in terms of transient pinning and depinning of the contact line on the surface of the particles. However, the nature of the pinning sites has not been investigated in detail. We use digital holographic microscopy to track a variety of colloidal spheres-inorganic and organic, charge-stabilized and sterically stabilized, aqueous and non-aqueous-as they breach liquid interfaces. We find that nearly all of these particles relax logarithmically in time over timescales much larger than those expected from viscous dissipation alone. By comparing our results to theoretical models of the pinning dynamics, we infer the area per defect to be on the order of a few square nanometers for each of the colloids we examine, whereas the energy per defect can vary from a few kT for non-aqueous and inorganic spheres to tens of kT for aqueous polymer particles. The results suggest that the likely pinning sites are topographical features inherent to colloidal particles-surface roughness in the case of silica particles and grafted polymer "hairs" in the case of polymer particles. We conclude that the slow relaxation must be taken into account in experiments and applications, such as Pickering emulsions, that involve colloids attaching to interfaces. The effect is particularly important for aqueous polymer particles, which pin the contact line strongly.
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Affiliation(s)
- Anna Wang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
| | - Ryan McGorty
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - David M Kaz
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Vinothan N Manoharan
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. and Department of Physics, Harvard University, Cambridge, MA 02138, USA
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13
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Zanini M, Isa L. Particle contact angles at fluid interfaces: pushing the boundary beyond hard uniform spherical colloids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:313002. [PMID: 27299800 DOI: 10.1088/0953-8984/28/31/313002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Micro and nanoparticles at fluid interfaces have been attracting increasing interest in the last few decades as building blocks for materials, as mechanical and structural probes for complex interfaces and as models for two-dimensional systems. The three-phase contact angle enters practically all aspects of the particle behavior at the interface: its thermodynamics (binding energy to the interface), dynamics (motion and drag at the interface) and interactions with the interface (adsorption and wetting). Moreover, many interactions among particles at the interface also strongly depend on the contact angle. These concepts have been extensively discussed for non-deformable, homogeneous and mostly spherical particles, but recent progress in particle synthesis and fabrication has instead moved in the direction of producing more complex micro and nanoscale objects, which can be responsive, deformable, heterogenous and/or anisotropic in shape, surface chemistry and material properties. These new particles have a much greater potential for applications and new science, and the study of their behavior at interfaces has only very recently started. In this paper, we critically review the current state of the art of the experimental methods available to measure the contact angle of micro and nanoparticles at fluid interfaces, indicating their strengths and limitations. We then comment on new particle systems that are currently attracting increasing interest in relation to their adsorption and assembly at fluid interfaces and discuss if and which ones of the current techniques are suited to investigate their properties at interfaces. Based on this discussion, we will finally try to indicate a direction in which new experimental methods should develop in the future to tackle the new challenges posed by the novel types of particles that more and more often are used at interfaces.
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Affiliation(s)
- Michele Zanini
- Department of Materials, Laboratory for Interfaces, Soft matter and Assembly, ETH Zurich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
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Pilat DW, Pouligny B, Best A, Nick TA, Berger R, Butt HJ. Surface forces between colloidal particles at high hydrostatic pressure. Phys Rev E 2016; 93:022608. [PMID: 26986378 DOI: 10.1103/physreve.93.022608] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Indexed: 11/07/2022]
Abstract
It was recently suggested that the electrostatic double-layer force between colloidal particles might weaken at high hydrostatic pressure encountered, for example, in deep seas or during oil recovery. We have addressed this issue by means of a specially designed optical trapping setup that allowed us to explore the interaction of a micrometer-sized glass bead and a solid glass wall in water at hydrostatic pressures of up to 1 kbar. The setup allowed us to measure the distance between bead and wall with a subnanometer resolution. We have determined the Debye lengths in water for salt concentrations of 0.1 and 1 mM. We found that in the pressure range from 1 bar to 1 kbar the maximum variation of the Debye lengths was <1 nm for both salt concentrations. Furthermore, the magnitude of the zeta potentials of the glass surfaces in water showed no dependency on pressure.
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Affiliation(s)
- D W Pilat
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - B Pouligny
- Centre de Recherche Paul-Pascal, 115 Avenue Schweitzer, 33600 Pessac, France
| | - A Best
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - T A Nick
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - R Berger
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - H-J Butt
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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15
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Kelleher CP, Wang A, Guerrero-García GI, Hollingsworth AD, Guerra RE, Krishnatreya BJ, Grier DG, Manoharan VN, Chaikin PM. Charged hydrophobic colloids at an oil-aqueous phase interface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:062306. [PMID: 26764691 DOI: 10.1103/physreve.92.062306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Indexed: 06/05/2023]
Abstract
Hydrophobic poly(methyl methacrylate) (PMMA) colloidal particles, when dispersed in oil with a relatively high dielectric constant, can become highly charged. In the presence of an interface with a conducting aqueous phase, image-charge effects lead to strong binding of colloidal particles to the interface, even though the particles are wetted very little by the aqueous phase. We study both the behavior of individual colloidal particles as they approach the interface and the interactions between particles that are already interfacially bound. We demonstrate that using particles which are minimally wetted by the aqueous phase allows us to isolate and study those interactions which are due solely to charging of the particle surface in oil. Finally, we show that these interactions can be understood by a simple image-charge model in which the particle charge q is the sole fitting parameter.
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Affiliation(s)
- Colm P Kelleher
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA
| | - Anna Wang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Guillermo Iván Guerrero-García
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA and Instituto de Fisica, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
| | - Andrew D Hollingsworth
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA
| | - Rodrigo E Guerra
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA
| | - Bhaskar Jyoti Krishnatreya
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA
| | - David G Grier
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA
| | - Vinothan N Manoharan
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Paul M Chaikin
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA
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16
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Parolini L, Law AD, Maestro A, Buzza DMA, Cicuta P. Interaction between colloidal particles on an oil-water interface in dilute and dense phases. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:194119. [PMID: 25924056 DOI: 10.1088/0953-8984/27/19/194119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The interaction between micron-sized charged colloidal particles at polar/non-polar liquid interfaces remains surprisingly poorly understood for a relatively simple physical chemistry system. By measuring the pair correlation function g(r) for different densities of polystyrene particles at the decane-water interface, and using a powerful predictor-corrector inversion scheme, effective pair-interaction potentials can be obtained up to fairly high densities, and these reproduce the experimental g(r) in forward simulations, so are self consistent. While at low densities these potentials agree with published dipole-dipole repulsion, measured by various methods, an apparent density dependence and long range attraction are obtained when the density is higher. This condition is thus explored in an alternative fashion, measuring the local mobility of colloids when confined by their neighbors. This method of extracting interaction potentials gives results that are consistent with dipolar repulsion throughout the concentration range, with the same magnitude as in the dilute limit. We are unable to rule out the density dependence based on the experimental accuracy of our data, but we show that incomplete equilibration of the experimental system, which would be possible despite long waiting times due to the very strong repulsions, is a possible cause of artefacts in the inverted potentials. We conclude that to within the precision of these measurements, the dilute pair potential remains valid at high density in this system.
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Affiliation(s)
- Lucia Parolini
- Cavendish Laboratory, University of Cambridge, The Old Schools, Trinity Ln, Cambridge CB2 1TN,UK
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17
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Majee A, Bier M, Dietrich S. Electrostatic interaction between colloidal particles trapped at an electrolyte interface. J Chem Phys 2014; 140:164906. [DOI: 10.1063/1.4872240] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Ray D, Aswal VK. Observation of adsorption versus depletion interaction for charged silica nanoparticles in the presence of non-ionic surfactant. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:035102. [PMID: 24285358 DOI: 10.1088/0953-8984/26/3/035102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The interaction of anionic silica nanoparticles (Ludox LS30) with non-ionic surfactant decaethylene glycol monododecylether (C12E10) without and in the presence of an electrolyte has been studied by small-angle neutron scattering (SANS) and dynamic light scattering (DLS). The measurements have been carried out for fixed concentrations of nanoparticles (1 wt%), surfactant (1 wt%) and electrolyte (0.1 M NaCl). In SANS, each of these nanoparticle-surfactant systems has been examined for three different contrast conditions where both (nanoparticle and surfactant) as well as individual components (nanoparticle or surfactant) are made visible. It is observed that the nanoparticle-surfactant systems behave very differently without and with the electrolyte. In the absence of salt, the C12E10 micelles form micelle decorated core-shell structures by adsorbing on the nanoparticles. On the other hand, the adsorption of surfactant micelles on nanoparticle is completely suppressed in the presence of salt, leading to the depletion-induced aggregation of nanoparticles. These results have also been corroborated by the DLS data. We thus show that the ionic strength of solution can be used to tune the interaction of ionic silica nanoparticles with non-ionic surfactant.
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Affiliation(s)
- D Ray
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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19
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Kumar S, Lee MJ, Aswal VK, Choi SM. Block-copolymer-induced long-range depletion interaction and clustering of silica nanoparticles in aqueous solution. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:042315. [PMID: 23679422 DOI: 10.1103/physreve.87.042315] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Indexed: 06/02/2023]
Abstract
Small-angle neutron scattering (SANS) has been carried out to examine the block-copolymer-induced depletion interaction of charged silica nanoparticles in aqueous solution. The measurements have been performed on fixed concentrations (1 and 10 wt. %) of anionic Ludox silica nanoparticles having sizes of 8 and 16 nm in the presence of 0.1M NaCl and varying concentration of polyethylene oxide-polypropylene oxide-polyethylene oxide P85 [(EO)(26)(PO)(39)(EO)(26)] block copolymer. The presence of the block copolymer induces an attractive depletion interaction between charge-stabilized nanoparticles. The effective interaction of silica nanoparticles is modeled by a combination of two Yukawa potentials accounting for attractive depletion and repulsive electrostatic forces. The depletion interaction is found to be a long-range attraction whose magnitude and range increase with block-copolymer concentration. The depletion interaction is further enhanced by tuning the self-assembly of the block copolymer through the variation of temperature. The increase of the depletion interaction ultimately leads to clustering of nanoparticles and is confirmed by the presence of a Bragg peak in the SANS data. The positioning of the Bragg peak suggests simple-cubic-type packing of particles within the clusters. The scattering from the clusters in the low-Q region is governed by the Porod scattering, indicating that clusters are quite large (order of microns). The depletion interaction is also found to be strongly dependent on the size of the nanoparticles.
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Affiliation(s)
- Sugam Kumar
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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Hur J, Mahynski NA, Won YY. Crystallization of bidisperse repulsive colloids in two-dimensional space: a study of model systems constructed at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11737-11749. [PMID: 20527939 DOI: 10.1021/la101313r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We report the structural behavior for mixtures of two differently sized ("bidisperse") silica microspheres at the air-water interface under three different size ratio conditions (alpha (identical with R(S)/R(L)) = 0.375, 0.500, and 0.579). These bidisperse silica monolayers were studied via measurement of the surface pressure-area isotherm and optical microscopy at various particle surface coverages (theta identical with theta(S) + theta(L)) during compression. The silica colloids used in these trials were found to possess purely repulsive pair interactions at the air-water interface, which was confirmed by the pair correlation function calculated from the analysis of many optical images of the particles taken at dilute concentrations. The results revealed that, at certain mixture compositions (beta identical with theta(L)/theta(S)), compression can lead to the formation of 2D binary crystal structures. Specifically, at a particle size ratio of alpha = 0.375, LS1 crystal domains were observed at a surface coverage of theta approximately 0.619 when beta = 7.00 and 3.50, although this LS1 structure was not observed at higher total particle densities (where the system became phase-separated). At a size ratio of alpha = 0.579, compression produced 2D LS2 binary crystals at particle surface coverages (theta) above 0.641 when beta = 3.00, 1.50, or 1.00. However, at a size ratio of alpha = 0.500, compression triggered macroscopic phase separation, leading to the formation of two separate hexagonal-close-packed domains consisting purely of either large or small particles. In general, when the mixture composition (beta) was too different from the stoichiometric ratio needed for the formation of LS1 or LS2 superlattices, the bidisperse monolayer was observed to remain in an amorphous state rather than evolving to an ordered phase under compression. These findings suggest that, in two dimensions, contrary to what has been speculated in the literature, (1) purely repulsive pair potentials can give rise to LS1 and LS2 binary crystals under compression and also (2) perfectly spherical particles can form LS2 crystals. This discrepancy between our results and the predictions of previous simulations might indicate that the capillary interaction and/or the many-body effects play a significant role in determining the structure of bidisperse colloids at the air-water interface.
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Affiliation(s)
- Jaehyun Hur
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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