1
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Kryuchkov NP, Nasyrov AD, Denisenko IR, Yurchenko SO. Interpolating the radial distribution function in a two-dimensional fluid across a wide temperature range. J Chem Phys 2024; 161:094505. [PMID: 39234969 DOI: 10.1063/5.0213689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 08/16/2024] [Indexed: 09/06/2024] Open
Abstract
Calculations of pair correlations in fluids usually require resource-intensive simulations or integral equations, while existing simple approximations lack accuracy. Here, we show that the pair correlation function for monolayer fluid-like systems can be decomposed into correlation peaks defined using Voronoi cells. Being properly normalized, these peaks exhibit a universal form, weak temperature dependence, and resemble those of an ideal gas, except for the first peak. As a result, we propose a simple and accurate approach to interpolate the pair correlation functions, suitable for molecular, colloids, and cellular fluids.
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Affiliation(s)
- Nikita P Kryuchkov
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, 105005 Moscow, Russia
| | - Artur D Nasyrov
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, 105005 Moscow, Russia
| | - Ilya R Denisenko
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, 105005 Moscow, Russia
| | - Stanislav O Yurchenko
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, 105005 Moscow, Russia
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2
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van Baalen C, Vialetto J, Isa L. Tuning Electrostatic Interactions of Colloidal Particles at Oil-Water Interfaces with Organic Salts. PHYSICAL REVIEW LETTERS 2023; 131:128202. [PMID: 37802948 DOI: 10.1103/physrevlett.131.128202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/23/2023] [Indexed: 10/08/2023]
Abstract
Monolayers of colloidal particles at oil-water interfaces readily crystallize owing to electrostatic repulsion, which is often mediated through the oil. However, little attempts exist to control it using oil-soluble electrolytes. We probe the interactions among charged hydrophobic microspheres confined at a water-hexadecane interface and show that repulsion can be continuously tuned over orders of magnitude upon introducing nanomolar amounts of an organic salt into the oil. Our results are compatible with an associative discharging mechanism of surface groups at the particle-oil interface, similar to the charge regulation observed for charged colloids in nonpolar solvents.
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Affiliation(s)
- Carolina van Baalen
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Jacopo Vialetto
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
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3
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Hybrid Nanoparticles at Fluid-Fluid Interfaces: Insight from Theory and Simulation. Int J Mol Sci 2023; 24:ijms24054564. [PMID: 36901995 PMCID: PMC10003740 DOI: 10.3390/ijms24054564] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023] Open
Abstract
Hybrid nanoparticles that combine special properties of their different parts have numerous applications in electronics, optics, catalysis, medicine, and many others. Of the currently produced particles, Janus particles and ligand-tethered (hairy) particles are of particular interest both from a practical and purely cognitive point of view. Understanding their behavior at fluid interfaces is important to many fields because particle-laden interfaces are ubiquitous in nature and industry. We provide a review of the literature, focusing on theoretical studies of hybrid particles at fluid-fluid interfaces. Our goal is to give a link between simple phenomenological models and advanced molecular simulations. We analyze the adsorption of individual Janus particles and hairy particles at the interfaces. Then, their interfacial assembly is also discussed. The simple equations for the attachment energy of various Janus particles are presented. We discuss how such parameters as the particle size, the particle shape, the relative sizes of different patches, and the amphiphilicity affect particle adsorption. This is essential for taking advantage of the particle capacity to stabilize interfaces. Representative examples of molecular simulations were presented. We show that the simple models surprisingly well reproduce experimental and simulation data. In the case of hairy particles, we concentrate on the effects of reconfiguration of the polymer brushes at the interface. This review is expected to provide a general perspective on the subject and may be helpful to many researchers and technologists working with particle-laden layers.
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4
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Guzmán E, Ortega F, Rubio RG. Forces Controlling the Assembly of Particles at Fluid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13313-13321. [PMID: 36278952 PMCID: PMC9648339 DOI: 10.1021/acs.langmuir.2c02038] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Indexed: 06/04/2023]
Abstract
The interaction of particles with fluid interfaces is ubiquitous in synthetic and natural work, involving two types of interactions: particle-interface interactions (trapping energy) and interparticle interactions. Therefore, it is urgent to gain a deep understanding of the main forces controlling the trapping of particles at fluid interfaces, and their assembly to generate a broad range of structures characterized by different degrees of order. This Perspective tries to provide an overview of the main contributions to the energetic landscape controlling the assembly of particles at fluid interfaces, which is essential for exploiting this type of interfacial systems as platforms for the fabrication of interface-based soft materials with technological interest.
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Affiliation(s)
- Eduardo Guzmán
- Departamento
de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040Madrid, Spain
- Instituto
Pluridisciplinar, Universidad Complutense
de Madrid, Paseo Juan XXIII 1, 28040Madrid, Spain
| | - Francisco Ortega
- Departamento
de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040Madrid, Spain
- Instituto
Pluridisciplinar, Universidad Complutense
de Madrid, Paseo Juan XXIII 1, 28040Madrid, Spain
| | - Ramón G. Rubio
- Departamento
de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040Madrid, Spain
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5
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Abstract
Studies of active matter-systems consisting of individuals or ensembles of internally driven and damped locomotors-are of interest to physicists studying nonequilibrium dynamics, biologists interested in individuals and swarm locomotion, and engineers designing robot controllers. While principles governing active systems on hard ground or within fluids are well studied, another class of systems exists at deformable interfaces. Such environments can display mixes of fluid-like and elastic features, leading to locomotor dynamics that are strongly influenced by the geometry of the surface, which, in itself, can be a dynamical entity. To gain insight into principles by which locomotors are influenced via a deformation field alone (and can influence other locomotors), we study robot locomotion on an elastic membrane, which we propose as a model of active systems on highly deformable interfaces. As our active agent, we use a differential driven wheeled robotic vehicle which drives straight on flat homogeneous surfaces, but reorients in response to environmental curvature. We monitor the curvature field-mediated dynamics of a single vehicle interacting with a fixed deformation as well as multiple vehicles interacting with each other via local deformations. Single vehicles display precessing orbits in centrally deformed environments, while multiple vehicles influence each other by local deformation fields. The active nature of the system facilitates a differential geometry-inspired mathematical mapping from the vehicle dynamics to those of test particles in a fictitious "spacetime," allowing further understanding of the dynamics and how to control agent interactions to facilitate or avoid multivehicle membrane-induced cohesion.
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6
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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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7
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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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8
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Molaei M, Chisholm NG, Deng J, Crocker JC, Stebe KJ. Interfacial Flow around Brownian Colloids. PHYSICAL REVIEW LETTERS 2021; 126:228003. [PMID: 34152169 DOI: 10.1103/physrevlett.126.228003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 03/21/2021] [Accepted: 04/08/2021] [Indexed: 06/13/2023]
Abstract
Understanding the flow created by particle motion at interfaces is a critical step toward understanding hydrodynamic interactions and colloidal self organization. We have developed correlated displacement velocimetry to measure flow fields around interfacially trapped Brownian particles. These flow fields can be decomposed into interfacial hydrodynamic multipoles, including force monopole and dipole flows. These structures provide key insights essential to understanding the interface's mechanical response. Importantly, the flow structure shows that the interface is incompressible for scant surfactant near the ideal gaseous state and contains information about interfacial properties and hydrodynamic coupling with the bulk fluid. The same dataset can be used to predict the response of the interface to applied, complex forces, enabling virtual experiments that produce higher order interfacial multipoles.
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Affiliation(s)
- Mehdi Molaei
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Nicholas G Chisholm
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jiayi Deng
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - John C Crocker
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Kathleen J Stebe
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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9
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Pérez-Juárez D, Sánchez R, Díaz-Leyva P, Kozina A. Equilibrium clustering of colloidal particles at an oil/water interface due to competing long-range interactions. J Colloid Interface Sci 2020; 571:232-238. [PMID: 32200167 DOI: 10.1016/j.jcis.2020.03.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 10/24/2022]
Abstract
HYPOTHESIS Colloids at fluid interfaces organize according to inter-particle interactions. The main contributions to an effective interaction potential are expected to be electrostatic dipole-dipole repulsion and capillary attraction due to fluid interface deformation. When these interactions are weak, a secondary minimum in the particle pair interaction potential is expected. EXPERIMENTS Clean bare silica particles were deposited at an oil/water interface and their organization as well as dynamics were observed under a light microscope and analyzed in terms of radial distribution function and mean squared displacement. FINDINGS Weak long-range competing interactions between colloids at an oil/water interface result in cluster formation. The clusters have a liquid-like structure and grow with increasing particle packing fraction. System 'ergodicity' suggests near-equilibrium assembly, which is confirmed by free particle dynamics outside the clusters. The interplay between dipole-dipole repulsion and capillary attraction responsible for the cluster formation is reflected in a secondary minimum of the effective interaction potential predicted theoretically but inaccessible experimentally from collective particle properties prior to this work.
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Affiliation(s)
- David Pérez-Juárez
- Instituto de Química, Universidad Nacional Autónoma de México, P.O. Box 70-213, 04510 Mexico City, Mexico
| | - Rodrigo Sánchez
- Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, 09340 Mexico City, Mexico
| | - Pedro Díaz-Leyva
- Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, 09340 Mexico City, Mexico
| | - Anna Kozina
- Instituto de Química, Universidad Nacional Autónoma de México, P.O. Box 70-213, 04510 Mexico City, Mexico.
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10
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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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11
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Abstract
Over the last two decades, understanding of the attachment of colloids to fluid interfaces has attracted the interest of researchers from different fields. This is explained by considering the ubiquity of colloidal and interfacial systems in nature and technology. However, to date, the control and tuning of the assembly of colloids at fluid interfaces remain a challenge. This review discusses some of the most fundamental aspects governing the organization of colloidal objects at fluid interfaces, paying special attention to spherical particles. This requires a description of different physicochemical aspects, from the driving force involved in the assembly to its thermodynamic description, and from the interactions involved in the assembly to the dynamics and rheological behavior of particle-laden interfaces.
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12
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Rey M, Yu T, Guenther R, Bley K, Vogel N. A Dirty Story: Improving Colloidal Monolayer Formation by Understanding the Effect of Impurities at the Air/Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:95-103. [PMID: 30543431 DOI: 10.1021/acs.langmuir.8b02605] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Colloidal monolayers are important tools to fabricate surface structures at the nanoscale. A typical monolayer fabrication strategy involves the self-assembly of colloidal building blocks at liquid interfaces, which are subsequently deposited on a solid substrate. Even though this process is well established, the resulting order of the particles within the colloidal monolayer differs between batches of colloidal particles and can even change with the age of the dispersion. In this study, we investigate the origins of this variation of monolayer quality for polystyrene particles synthesized by surfactant-free emulsion polymerization. We correlate the interfacial behavior of the colloidal particles at the air/water interface on a Langmuir trough with the resulting quality of the monolayer after transfer to a solid substrate. We identify surface-active impurities as a major cause for a disturbed self-assembly of the colloidal particles. These impurities form during the particle synthesis and consist of copolymers of styrene, the comonomer acrylic acid, and sulfonate species from the initiator. We show that they can be removed by cleaning protocols to increase the monolayer quality. However, our experiments demonstrate that the impurities reappear over time even for cleaned dispersions, indicating desorption from the surface of the colloidal particles. We identify strategies to avoid the presence of the impurities at the air/water interface or to inhibit their effect on the self-assembly process. These simple guidelines improve the quality of the resulting colloidal monolayer, which is a prerequisite for the reliable fabrication of high-quality surface nanostructures from colloidal templates.
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Affiliation(s)
- Marcel Rey
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
| | - Taotao Yu
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
| | - Roman Guenther
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
| | - Karina Bley
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
| | - Nicolas Vogel
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
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13
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Somerville WRC, Stokes JL, Adawi AM, Horozov TS, Archer AJ, Buzza DMA. Density functional theory for the crystallization of two-dimensional dipolar colloidal alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:405102. [PMID: 30160237 DOI: 10.1088/1361-648x/aaddc9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-dimensional mixtures of dipolar colloidal particles with different dipole moments exhibit extremely rich self-assembly behaviour and are relevant to a wide range of experimental systems, including charged and super-paramagnetic colloids at liquid interfaces. However, there is a gap in our understanding of the crystallization of these systems because existing theories such as integral equation theory and lattice sum methods can only be used to study the high temperature fluid phase and the zero-temperature crystal phase, respectively. In this paper we bridge this gap by developing a density functional theory (DFT), valid at intermediate temperatures, in order to study the crystallization of one and two-component dipolar colloidal monolayers. The theory employs a series expansion of the excess Helmholtz free energy functional, truncated at second order in the density, and taking as input highly accurate bulk fluid direct correlation functions from simulation. Although truncating the free energy at second order means that we cannot determine the freezing point accurately, our approach allows us to calculate ab initio both the density profiles of the different species and the symmetry of the final crystal structures. Our DFT predicts hexagonal crystal structures for one-component systems, and a variety of superlattice structures for two-component systems, including those with hexagonal and square symmetry, in excellent agreement with known results for these systems. The theory also provides new insights into the structure of two-component systems in the intermediate temperature regime where the small particles remain molten but the large particles are frozen on a regular lattice.
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Affiliation(s)
- W R C Somerville
- G. W. Gray Centre for Advanced Materials, School of Mathematics & Physical Sciences, University of Hull, Hull HU6 7RX, United Kingdom
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14
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Kelleher CP, Guerra RE, Hollingsworth AD, Chaikin PM. Phase behavior of charged colloids at a fluid interface. Phys Rev E 2017; 95:022602. [PMID: 28297978 DOI: 10.1103/physreve.95.022602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Indexed: 06/06/2023]
Abstract
We study the phase behavior of a system of charged colloidal particles that are electrostatically bound to an almost flat interface between two fluids. We show that, despite the fact that our experimental system consists of only 10^{3}-10^{4} particles, the phase behavior is consistent with the theory of melting due to Kosterlitz, Thouless, Halperin, Nelson, and Young. Using spatial and temporal correlations of the bond-orientational order parameter, we classify our samples into solid, isotropic fluid, and hexatic phases. We demonstrate that the topological defect structure we observe in each phase corresponds to the predictions of Kosterlitz-Thouless-Halperin-Nelson-Young theory. By measuring the dynamic Lindemann parameter γ_{L}(τ) and the non-Gaussian parameter α_{2}(τ) of the displacements of the particles relative to their neighbors, we show that each of the phases displays distinctive dynamical behavior.
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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
| | - Rodrigo E Guerra
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA
| | - Andrew D Hollingsworth
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, 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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15
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Buttinoni I, Steinacher M, Spanke HT, Pokki J, Bahmann S, Nelson B, Foffi G, Isa L. Colloidal polycrystalline monolayers under oscillatory shear. Phys Rev E 2017; 95:012610. [PMID: 28208468 DOI: 10.1103/physreve.95.012610] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Indexed: 11/07/2022]
Abstract
In this paper we probe the structural response to oscillatory shear deformations of polycrystalline monolayers of soft repulsive colloids with varying area fraction over a broad range of frequencies and amplitudes. The particles are confined at a fluid interface, sheared using a magnetic microdisk, and imaged through optical microscopy. The structural and mechanical response of soft materials is highly dependent on their microstructure. If crystals are well understood and deform through the creation and mobilization of specific defects, the situation is much more complex for disordered jammed materials, where identifying structural motifs defining plastically rearranging regions remains an elusive task. Our materials fall between these two classes and allow the identification of clear pathways for structural evolution. In particular, we demonstrate that large enough strains are able to fluidize the system, identifying critical strains that fulfill a local Lindemann criterion. Conversely, smaller strains lead to localized and erratic irreversible particle rearrangements due to the motion of structural defects. In this regime, oscillatory shear promotes defect annealing and leads to the growth of large crystalline domains. Numerical simulations help identify the population of rearranging particles with those exhibiting the largest deviatoric stresses and indicate that structural evolution proceeds towards the minimization of the stress stored in the system. The particles showing high deviatoric stresses are localized around grain boundaries and defects, providing a simple criterion to spot regions likely to rearrange plastically under oscillatory shear.
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Affiliation(s)
- Ivo Buttinoni
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Mathias Steinacher
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Hendrik Th Spanke
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Severin Bahmann
- Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Bradley Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Giuseppe Foffi
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay 91405, France
| | - Lucio Isa
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
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16
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Gratale MD, Ma X, Davidson ZS, Still T, Habdas P, Yodh AG. Vibrational properties of quasi-two-dimensional colloidal glasses with varying interparticle attraction. Phys Rev E 2016; 94:042606. [PMID: 27841543 DOI: 10.1103/physreve.94.042606] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 06/06/2023]
Abstract
We measure the vibrational modes and particle dynamics of quasi-two-dimensional colloidal glasses as a function of interparticle interaction strength. The interparticle attractions are controlled via a temperature-tunable depletion interaction. Specifically, the interparticle attraction energy is increased gradually from a very small value (nearly hard-sphere) to moderate strength (∼4k_{B}T), and the variation of colloidal particle dynamics and vibrations are concurrently probed. The particle dynamics slow monotonically with increasing attraction strength, and the particle motions saturate for strengths greater than ∼2k_{B}T, i.e., as the system evolves from a nearly repulsive glass to an attractive glass. The shape of the phonon density of states is revealed to change with increasing attraction strength, and the number of low-frequency modes exhibits a crossover for glasses with weak compared to strong interparticle attraction at a threshold of ∼2k_{B}T. This variation in the properties of the low-frequency vibrational modes suggests a new means for distinguishing between repulsive and attractive glass states.
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Affiliation(s)
- Matthew D Gratale
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Xiaoguang Ma
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Complex Assemblies of Soft Matter, CNRS-Solvay-UPenn UMI 3254, Bristol, Pennsylvania 19007-3624, USA
| | - Zoey S Davidson
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tim Still
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Piotr Habdas
- Department of Physics, Saint Joseph's University, Philadelphia, Pennsylvania 19131, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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17
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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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