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Shen Q, Dai H, Wen L, Zheng W, Li B, Dai J, Li B, Chen Y. Effects of pH-shifting treatments on the emulsifying properties of rice protein isolates: Quantitative analysis of interfacial protein layer. Food Res Int 2023; 164:112306. [PMID: 36737901 DOI: 10.1016/j.foodres.2022.112306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022]
Abstract
For the limitation of poor solubility and interfacial adsorption capacity of rice protein isolates (RPI), in this work the effects of pH-shifting treatments on the emulsifying properties of RPI were investigated. The results showed that the particle size of the emulsion stabilized by alkaline pH-shifting treated RPI was smaller than that stabilized by acid pH-shifting treated RPI. In addition, the RPI-10 stabilized emulsion showed a more uniform particle size distribution, which was explained by its high emulsifying activity and stability (EAI: 49.5 m2/g, ESI: 59.5 min). The interface rheology results showed that the alkaline pH-shifting treatment could promote the protein rearrangement and subsequently formed interface film with higher rate of protein penetration and rearrangement. The quantitative analysis of adsorbed proteins in the RPI-10 stabilized emulsion showed that glutelin-type isoforms as major proteins in RPI were increased at the oil-water interface for their balanced distribution of the hydrophilic and hydrophobic amino acid group. These quantitative and interfacial rheology analysis could improve deep understanding of the interfacial properties of pH-shifting treated RPI, and promote the development of application in grain protein stabilized emulsion.
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Affiliation(s)
- Qian Shen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hongmin Dai
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Luming Wen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Wei Zheng
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Beixi Li
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jun Dai
- Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, China
| | - Bin Li
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yijie Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Wuhan 430070, China; Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124, China.
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2
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Active Colloids on Fluid Interfaces. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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3
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Hydrodynamic interactions between charged and uncharged Brownian colloids at a fluid-fluid interface. J Colloid Interface Sci 2022; 628:931-945. [PMID: 36037716 DOI: 10.1016/j.jcis.2022.08.084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/24/2022]
Abstract
HYPOTHESIS The cluster formation and self-assembly of floating colloids at a fluid/fluid interface is a delicate force balance involving deterministic lateral interaction forces, viscous resistance to relative colloid motion along the surface and thermal (Brownian) fluctuations. As the colloid dimensions get smaller, thermal forces and associated drag forces become important and can affect the self assembly into ordered patterns and crystal structures that are the starting point for various materials applications. NUMERICS Langevin dynamic simulations for particle pairs straddling a liquid-liquid interface with a high viscosity contrast are presented to describe the lateral interfacial assembly of particles in Brownian and non-Brownian dominated regimes. These simulations incorporate capillary attraction, electrostatic repulsion, thermal fluctuations and hydrodynamic interactions (HI) between particles (including the effect of the particle immersion depth). Simulation results are presented for neutrally wetted particles which form a contact angle θ=900 at the interface. FINDINGS The simulation results suggest that clustering, fractal growth and particle ordering become favorable outcomes at critically large values of the Pe numbers, while smaller Pe numbers exhibit higher probabilities of final configurations where particle motion remains uncorrelated in space and particle pairs are found to be more widely separated especially upon the introduction of HI.
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4
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Song Y, Yu W, Liu Z, Huang Y, Li M, Li D. Electrokinetic transportation and differentiation of copper and aluminum particles in oil with an oil-water interface. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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5
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Wang C, Gao Q. 3D Numerical Study of the Electrokinetic Motion of a Microparticle Adsorbed at a Horizontal Oil/Water Interface in an Infinite Domain. ACS OMEGA 2022; 7:4062-4070. [PMID: 35155900 PMCID: PMC8830061 DOI: 10.1021/acsomega.1c05405] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
This work builds a three-dimensional (3D) simulation model and studies the electrokinetic velocity of a microparticle adsorbed at a horizontal oil/water interface in an infinite domain. The effects of the interface zeta potentials, the electric field, the oil dynamic viscosity, and the contact angle between the particle and the oil/water interface are investigated in detail. The results show that in an infinite oil/water interface system, both the negatively charged mobile oil/water interface and the negatively charged particle adsorbed to it move toward the positive electrode of the DC electric field, and the particle velocity increases along with the contact angle, the electric field strength, and the absolute values of negative zeta potential of both the particle and the oil/water interface. When the oil/water interface is positively charged with a relatively small zeta potential, the negatively charged microparticle also moves in the opposite direction of the electric field. The larger the oil dynamic viscosity, the smaller the electrokinetic velocity of the microparticle at the interface. Additionally, the numerical simulation results are compared with the reported experiment results under the same conditions, and they have good agreement.
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6
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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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7
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Molecular Dynamics Study of Structural Properties of Refining Slag with Various CaO/Al2O3 Ratios. MINERALS 2021. [DOI: 10.3390/min11040398] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
SiO2-Al2O3-CaO-MgO is the main type of refining slag in a ladle furnace. Here the effects of the CaO/Al2O3 mass ratio on the structural properties of the refining slag system are studied by molecular dynamics simulations. The pair distribution function, coordination number, micro-structure unit and diffusion capacity were analyzed. An increase in the CaO/Al2O3 ratio did not change the bond lengths of these units. However, an increase of the CaO/Al2O3 ratio caused more charge compensators to be introduced into the refining slag system, which led to conversion of free oxygen and non-bridging oxygen to tricluster oxygen and bridging oxygen in the system. Moreover, this augmented the content of relatively stable 4- and 5-coordinate Al. As the micro-structure of the system became more complex, the overall diffusion capacity of the refining slag became poorer. In the micro-structure, the diffusion capabilities of different atoms decreased in the following order: Mg > Ca > O > Al > Si.
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Hemauer J, Qiu M, Feng JJ, Loudet JC. Particle rotation speeds up capillary interactions. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:30. [PMID: 33721135 DOI: 10.1140/epje/s10189-021-00025-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
We use dynamic numerical simulations to investigate the role of particle rotation in pairwise capillary interactions of particles trapped at a fluid interface. The fluid interface is modeled with a phase-field method which is coupled to the Navier-Stokes equations to solve for the flow dynamics. Numerical solutions are found using a finite element scheme in a bounded two-dimensional geometry. The interfacial deformations are caused by the buoyant weight of the particles, which are allowed to both translate and rotate due to the capillary and viscous forces and torques at play. The results show that the capillary attraction is faster between freely rotating particles than if particle rotation is inhibited, and the higher the viscosity mismatch, the greater the effect. To explain this result, we analyze the drag force exerted on the particles and find that the translational drag force on a rotating particle is always less than its non-rotating counterpart due to attenuated velocity gradients in the vicinity of the particle. We also find that the influence of interfacial deformations on particle rotation is minute.
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Affiliation(s)
- J Hemauer
- Department of Mechanical Engineering, Technical University of Munich, 85748, Garching, Germany
- Department of Mathematics, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada
| | - M Qiu
- Department of Mathematics, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada
- Laboratoire de Physique, École Normale Supérieure, 75005, Paris, France
| | - J J Feng
- Department of Mathematics, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - J-C Loudet
- Department of Mathematics, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada.
- CNRS, Centre de Recherche Paul Pascal (UMR 5031), University of Bordeaux, 33600, Pessac, France.
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9
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Feng X, Dai H, Ma L, Fu Y, Yu Y, Zhou H, Guo T, Zhu H, Wang H, Zhang Y. Properties of Pickering emulsion stabilized by food-grade gelatin nanoparticles: influence of the nanoparticles concentration. Colloids Surf B Biointerfaces 2020; 196:111294. [DOI: 10.1016/j.colsurfb.2020.111294] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 01/25/2023]
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10
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Loudet JC, Qiu M, Hemauer J, Feng JJ. Drag force on a particle straddling a fluid interface: Influence of interfacial deformations. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2020; 43:13. [PMID: 32060763 DOI: 10.1140/epje/i2020-11936-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
We numerically investigate the influence of interfacial deformations on the drag force exerted on a particle straddling a fluid interface. We perform finite element simulations of the two-phase flow system in a bounded two-dimensional geometry. The fluid interface is modeled with a phase-field method which is coupled to the Navier-Stokes equations to solve for the flow dynamics. The interfacial deformations are caused by the buoyant weight of the particle, which results in curved menisci. We compute drag coefficients as a function of the three-phase contact angle, the viscosity ratio of the two fluids, and the particle density. Our results show that, for some parameter values, large drag forces are not necessarily correlated with large interfacial distortions and that a lower drag may actually be achieved with non-flat interfaces rather than with unperturbed ones.
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Affiliation(s)
- J -C Loudet
- University of Bordeaux, CNRS, Centre de Recherche Paul Pascal (UMR 5031), F-33600, Pessac, France.
- University of British Columbia, Department of Mathematics, V6T 1Z2, Vancouver, BC, Canada.
| | - M Qiu
- University of British Columbia, Department of Mathematics, V6T 1Z2, Vancouver, BC, Canada
| | - J Hemauer
- University of British Columbia, Department of Mathematics, V6T 1Z2, Vancouver, BC, Canada
| | - J J Feng
- University of British Columbia, Department of Mathematics, V6T 1Z2, Vancouver, BC, Canada
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11
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Maestro A, Santini E, Guzmán E. Physico-chemical foundations of particle-laden fluid interfaces. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:97. [PMID: 30141087 DOI: 10.1140/epje/i2018-11708-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 07/27/2018] [Indexed: 06/08/2023]
Abstract
Particle-laden interfaces are ubiquitous nowadays. The understanding of their properties and structure is essential for solving different problems of technological and industrial relevance; e.g. stabilization of foams, emulsions and thin films. These rely on the response of the interface to mechanical perturbations. The complex mechanical response appearing in particle-laden interfaces requires deepening on the understanding of physico-chemical mechanisms underlying the assembly of particles at interface which plays a central role in the distribution of particles at the interface, and in the complex interfacial dynamics appearing in these systems. Therefore, the study of particle-laden interfaces deserves attention to provide a comprehensive explanation on the complex relaxation mechanisms involved in the stabilization of fluid interfaces.
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Affiliation(s)
- Armando Maestro
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042, Grenoble, Cedex 9, France
| | - Eva Santini
- Istituto di Chimica della Materia Condensata e di Tecnologia per l'Energia (ICMATE), U.O.S. Genova-Consiglio Nazionale delle Ricerche (CNR), Via De Marini 6, 16149, Genova, Italy
| | - Eduardo Guzmán
- Departamento de Química Física I, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII, 1, 28040, Madrid, Spain.
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12
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Das S, Koplik J, Farinato R, Nagaraj DR, Maldarelli C, Somasundaran P. The Translational and Rotational Dynamics of a Colloid Moving Along the Air-Liquid Interface of a Thin Film. Sci Rep 2018; 8:8910. [PMID: 29891986 PMCID: PMC5995853 DOI: 10.1038/s41598-018-26121-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/02/2018] [Indexed: 11/16/2022] Open
Abstract
This study examines the translation and rotation of a spherical colloid straddling the (upper) air/liquid interface of a thin, planar, liquid film bounded from below by either a solid or a gas/liquid interface. The goal is to obtain numerical solutions for the hydrodynamic flow in order to understand the influence of the film thickness and the lower interface boundary condition. When the colloid translates on a film above a solid, the viscous resistance increases significantly as the film thickness decreases due to the fluid-solid interaction, while on a free lamella, the drag decreases due to the proximity to the free (gas/liquid) surface. When the colloid rotates, the contact line of the interface moves relative to the colloid surface. If no-slip is assumed, the stress becomes infinite and prevents the rotation. Here finite slip is used to resolve the singularity, and for small values of the slip coefficient, the rotational viscous resistance is dominated by the contact line stress and is surprisingly less dependent on the film thickness and the lower interface boundary condition. For a colloid rotating on a semi-infinite liquid layer, the rotational resistance is largest when the colloid just breaches the interface from the liquid side.
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Affiliation(s)
- Subhabrata Das
- Columbia University, Langmuir Center of Colloids and Interfaces, New York, 10025, USA
| | - Joel Koplik
- City College of The City University of New York, Levich Institute and Department of Physics, New York, 10027, USA
| | | | | | - Charles Maldarelli
- City College of The City University of New York, Levich Institute and Department of Chemical Engineering, New York, 10027, USA
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13
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Laal Dehghani N, Khare R, Christopher GF. 2D Stokesian Approach to Modeling Flow Induced Deformation of Particle Laden Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:904-916. [PMID: 28877439 DOI: 10.1021/acs.langmuir.7b02448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A Stokesian dynamics simulation of the effect of surface Couette flow on the microstructure of particles irreversibly adsorbed to an interface is presented. Rather than modeling both bulk phases, the interface, and particles in a full 3D simulation, known interfacial interactions between adsorbed particles are used to create a 2D model from a top down perspective. This novel methodology is easy to implement and computationally inexpensive, which makes it favorable to simulate behavior of particles under applied flow at fluid-fluid interfaces. The methodology is used to examine microstructure deformation of monodisperse, rigid spherical colloids with repulsive interactions when a surface Couette flow is imposed. Simulation results compare favorably to experimental results taken from literature, showing that interparticle forces must be 1 order of magnitude greater than viscous drag for microstructure to transition from aligned particle strings to rotation of local hexagonal domains. Additionally, it is demonstrated that hydrodynamic interactions between particles play a significant role in the magnitude of these microstructure deformations.
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Affiliation(s)
- Nader Laal Dehghani
- Texas Tech University , Edward E. Whitacre Jr. College of Engineering, Department of Mechanical Engineering, P.O. Box 41021, Lubbock, Texas 79409, United States
| | - Rajesh Khare
- Texas Tech University , Edward E. Whitacre Jr. College of Engineering, Department of Chemical Engineering, Sixth Street and Canton Avenue, Lubbock, Texas 79409, United States
| | - Gordon F Christopher
- Texas Tech University , Edward E. Whitacre Jr. College of Engineering, Department of Mechanical Engineering, P.O. Box 41021, Lubbock, Texas 79409, United States
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Kang DW, Lee M, Kim KH, Xia M, Im SH, Park BJ. Electrostatic interactions between particles through heterogeneous fluid phases. SOFT MATTER 2017; 13:6647-6658. [PMID: 28926066 DOI: 10.1039/c7sm01309d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigated the electrostatic interactions between particles acting through heterogeneous fluid phases. An oil lens system floating on the surface of water was used to trap particles at different fluid-fluid interfaces. The inner particles are located at the centrosymmetrically curved oil-water interface inside the oil lens while satellite particles are located at the curved air-water interface, separated by a particular distance from the triple phase boundary. The satellite particles are likely to be captured in an energy minimum state due to electrostatic repulsions by the inner particles balanced with the gravity-induced potential energy. As the size of the oil lens decreases upon evaporation, the satellite particles escape from the gravitational confinement at a critical moment. The self-potential values of the inner particles and the satellite particles were calculated by employing an energy balance and the experimentally obtained geometric parameter values. It was found that the self-potential values of the inner particles decrease as oil evaporates over time and that the magnitude of the self-potential of the satellite particles is a hundred times larger than that of the inner particles. These results demonstrate significant effects of the thickness and shape of the nonpolar superphase on the electrostatic interactions between the particles trapped at different fluid-fluid interfaces.
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Affiliation(s)
- Dong Woo Kang
- Department of Chemical Engineering, Kyung Hee University, Yongin, 17104, South Korea.
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15
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Cappelli S, de Jong AM, Baudry J, Prins MWJ. Interparticle Capillary Forces at a Fluid-Fluid Interface with Strong Polymer-Induced Aging. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:696-705. [PMID: 28036188 DOI: 10.1021/acs.langmuir.6b03910] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on a measurement of forces between particles adsorbed at a water-oil interface in the presence of an oil-soluble polymer. The cationic polymer interacts electrostatically with the negatively charged particles, thereby modulating the particle contact angle and the magnitude of capillary attraction between the particles. However, polymer adsorption to the interface also generates an increase in the apparent interfacial viscosity over several orders of magnitude in a time span of a few hours. We have designed an experiment in which repeated motion trajectories are measured on pairs of particles. The experiment gives an independent quantification of the interfacial drag coefficient (10-7-10-4 Ns/m) and of the interparticle capillary forces (0.1-10 pN). We observed that the attractive capillary force depends on the amount of polymer in the oil phase and on the particle pair. However, the attraction appears to be independent of the surface rheology, with changes over a wide range of apparent viscosity values due to aging. Given the direction (attraction), the range (∼μm), and the distance dependence (∼1/S5) of the observed interparticle force, we interpret the force as being caused by quadrupolar deformations of the fluid-fluid interface induced by particle surface roughness. The results suggest that capillary forces are equilibrated in the early stages of interface aging and thereafter do not change anymore, even though strong changes in surface rheology still occur. The described experimental approach is powerful for studying dissipative as well as conservative forces of micro- and nanoparticles at fluid-fluid interfaces for systems out of equilibrium.
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Affiliation(s)
| | | | - Jean Baudry
- Laboratoire Colloïdes et Matériaux Divisés (LCMD), ESPCI Paris, PSL Research University, CNRS UMR8231 Chimie Biologie Innovation, F-75005, Paris, France
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16
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Lee DG, Cicuta P, Vella D. Self-assembly of repulsive interfacial particles via collective sinking. SOFT MATTER 2016; 13:212-221. [PMID: 27357475 DOI: 10.1039/c6sm00901h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Charged colloidal particles trapped at an air-water interface are well known to form an ordered crystal, stabilized by a long ranged repulsion; the details of this repulsion remain something of a mystery, but all experiments performed to date have confirmed a dipolar-repulsion, at least at dilute concentrations. More complex arrangements are often observed, especially at higher concentration, and these seem to be incompatible with a purely repulsive potential. In addition to electrostatic repulsion, interfacial particles may also interact via deformation of the surface: so-called capillary effects. Pair-wise capillary interactions are well understood, and are known to be too small (for these colloidal particles) to overcome thermal effects. Here we show that collective effects may significantly modify the simple pair-wise interactions and become important at higher density, though we remain well below close packing throughout. In particular, we show that the interaction of many interfacial particles can cause much larger interfacial deformations than do isolated particles, and show that the energy of interaction per particle due to this "collective sinking" grows as the number of interacting particles grows. Though some of the parameters in our simple model are unknown, the scaling behaviour is entirely consistent with experimental data, strongly indicating that estimating interaction energy based solely on pair-wise potentials may be too simplistic for surface particle layers.
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Affiliation(s)
- Duck-Gyu Lee
- Mathematical Institute, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
| | | | - Dominic Vella
- Mathematical Institute, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
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17
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Kassuga TD, Rothstein JP. The effect of shear and confinement on the buckling of particle-laden interfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:025101. [PMID: 26658075 DOI: 10.1088/0953-8984/28/2/025101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this paper, we investigate the buckling of an air-water interface populated by lycopodium powder particles using a specially designed Langmuir trough with side walls that deformed affinely with the particle-laden interface in order to minimize the effect of shear during compression. Confinement effects from the side walls were studied by systematically reducing the width of the Langmuir trough and measuring the buckling wavelength. For interfaces wider than 20 mm, the bulk wavelength was found to be independent of interface width. Due to the presence of contact line friction along the sidewall, the amplitude and wavelength of the wrinkles near the side walls were found to be reduced by a factor two compared with the bulk. A cascade in wavelength was observed as one moved from the center of the particle-laden interface towards the sidewalls similar to what has been observed for thin floating polymer films. For interface widths less than 20 mm, the wavelength of the wrinkles in the bulk was found to decrease eventually approaching the wavelength measured along the side walls. The wavelength at the walls was not affected by confinement. At large compressive strains, a transition from wrinkles to folds was observed. These regions of strain localization formed as a train of folds shortly after the onset of wrinkling and grew in amplitude with increasing compression. Confinement was also found to have an impact on folding. To study the impact of shear during interface compression, a series of objects including circular cylinders and rectangular prisms were placed through the center of the particle-laden interface before compression. These objects enhanced wrinkling and folding upstream of the object, eliminated wrinkling and folding in a broad region downstream of the object, and realigned the wrinkles along the side of the immobile obstacles where shear strains were maximum.
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Affiliation(s)
- Theo D Kassuga
- Department of Mechanical and Industrial Engineering, University of Massachusetts - Amherst, 160 Governors Drive, Amherst, MA 01003, USA
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18
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Dani A, Keiser G, Yeganeh M, Maldarelli C. Hydrodynamics of Particles at an Oil-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13290-302. [PMID: 26488685 DOI: 10.1021/acs.langmuir.5b02146] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This study is a theoretical and experimental investigation of the hydrodynamics of the mutual approach of two floating spherical particles moving along an oil-water interface. An analytical expression is obtained for the (inertialess) Stokes drag for an isolated particle translating on a flat interface as a function of the immersion depth into the water phase for the case in which the viscosity of the oil is much larger than that of the water. An approximation for the viscous drag due to the mutual approach of identical spheres is formulated as the product of the isolated drag multiplied by the resistance of approaching spheres in an infinite medium. Experiments are undertaken on the capillary attraction of large, millimeter-sized Teflon spheres floating at the interface between a very viscous oil and water. With the use of image visualization and particle tracking, the separation distance as a function of time [[Formula: see text](t)] is measured along with the immersion depth and predicted by setting the capillary attraction force equal to the viscous drag resistance. The excellent agreement validates the approximating formula.
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Affiliation(s)
- Archit Dani
- The Benjamin Levich Institute for PhysicoChemical Hydrodynamics and Department of Chemical Engineering, The City College of New York , 140 Convent Avenue, New York, NY 10031, United States
| | - Geoff Keiser
- ExxonMobil Research and Engineering Company , Annandale, NJ 08801, United States
| | - Mohsen Yeganeh
- ExxonMobil Research and Engineering Company , Annandale, NJ 08801, United States
| | - Charles Maldarelli
- The Benjamin Levich Institute for PhysicoChemical Hydrodynamics and Department of Chemical Engineering, The City College of New York , 140 Convent Avenue, New York, NY 10031, United States
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Monolayers of charged particles in a Langmuir trough: Could particle aggregation increase the surface pressure? J Colloid Interface Sci 2015; 462:223-34. [PMID: 26454382 DOI: 10.1016/j.jcis.2015.09.075] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/30/2015] [Indexed: 11/22/2022]
Abstract
The effect of aggregation on the surface pressure, Π, of monolayers from charged micrometer-sized colloidal particles on the air/water interface is investigated. Π is completely due to the long-range electrostatic repulsion between the particles mediated by their electrostatic field in the air. The most probable origin of particle aggregation is the attraction between capillary quadrupoles due to undulated contact lines on particle surfaces. Aggregates have higher charge and repel each other stronger than single particles. The data analysis by means of a theoretical model implies that Π linearly increases with n(1/2); n is the mean aggregation number, which can be determined from the experimental Π vs. area curves. The presence of electrolyte promotes aggregation, which tends to increase Π, but simultaneously reduces the surface charge that leads to lower Π. For our system, the first effect prevails and apparently paradoxical behavior is observed: the addition of salt in water enhances the electrostatic surface pressure. The data indicate limited aggregation: the rise of the electrostatic barrier prevents the further coalescence of aggregates if they have become sufficiently large. The results contribute for a better understanding of the factors that control the interactions in monolayers of charged particles at liquid interfaces.
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20
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Centrifugation-assisted Assembly of Colloidal Silica into Crack-Free and Transferrable Films with Tunable Crystalline Structures. Sci Rep 2015; 5:12100. [PMID: 26159121 PMCID: PMC4498329 DOI: 10.1038/srep12100] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 06/18/2015] [Indexed: 11/15/2022] Open
Abstract
Self-assembly of colloidal particles into colloidal films has many actual and potential applications. While various strategies have been developed to direct the assembly of colloidal particles, fabrication of crack-free and transferrable colloidal film with controllable crystal structures still remains a major challenge. Here we show a centrifugation-assisted assembly of colloidal silica spheres into free-standing colloidal film by using the liquid/liquid interfaces of three immiscible phases. Through independent control of centrifugal force and interparticle electrostatic repulsion, polycrystalline, single-crystalline and quasi-amorphous structures can be readily obtained. More importantly, by dehydration of silica particles during centrifugation, the spontaneous formation of capillary water bridges between particles enables the binding and pre-shrinkage of the assembled array at the fluid interface. Thus the assembled colloidal films are not only crack-free, but also robust and flexible enough to be easily transferred on various planar and curved substrates.
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21
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Buckling of particle-laden interfaces. J Colloid Interface Sci 2015; 448:287-96. [DOI: 10.1016/j.jcis.2015.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/03/2015] [Accepted: 02/03/2015] [Indexed: 11/22/2022]
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22
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Maestro A, Guzmán E, Ortega F, Rubio RG. Contact angle of micro- and nanoparticles at fluid interfaces. Curr Opin Colloid Interface Sci 2014. [DOI: 10.1016/j.cocis.2014.04.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Petkov PV, Danov KD, Kralchevsky PA. Surface pressure isotherm for a monolayer of charged colloidal particles at a water/nonpolar-fluid interface: experiment and theoretical model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2768-78. [PMID: 24559373 DOI: 10.1021/la500126d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Monolayers from electrically charged micrometer-sized silica particles, spread on the air/water interface, are investigated. Because of the electrostatic repulsion, the distances between the particles are considerably greater than their diameters, i.e., we are dealing with nondensely packed interfacial layers. The electrostatic repulsion between the particles occurs through the air phase. Surface pressure vs area isotherms were measured by Langmuir trough, and the monolayers' morphology was monitored by microscope. The mean area per particle is determined by Delaunay triangulation and Voronoi diagrams. In terms of mean area, the surface pressure for monolayers from polydisperse and monodisperse particles obeys the same law. The experiments show that Π ∝ L(-3) at large L, where Π is the surface pressure and L is the mean interparticle distance. A theoretical cell model is developed, which predicts not only the aforementioned asymptotic law but also the whole Π(L) dependence. The model presumes a periodic distribution of the surface charge density, which induces a corresponding electric field in the air phase. Then, the Maxwell pressure tensor of the electric field in the air phase is calculated and integrated according to the Bakker's formula to determine the surface pressure. Thus, all collective effects from the electrostatic interparticle interactions are taken into account as well as the effects from the particle finite size. By evaporation of water, the particle monolayers are deposited on a solid substrate placed on the bottom of the trough. The electrostatic interparticle repulsion is strong enough to withstand the attractive lateral capillary immersion forces that are operative during the drying of the monolayer on the substrate. The obtained experimental results and the developed theoretical model can be useful for prediction and control of the properties of nondensely packed interfacial monolayers from charged particles that find applications for producing micropatterned surfaces.
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Affiliation(s)
- Plamen V Petkov
- Department of Chemical Engineering, Faculty of Chemistry and Pharmacy, Sofia University , 1164 Sofia, Bulgaria
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24
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Forces acting on dielectric colloidal spheres at a water/nonpolar-fluid interface in an external electric field. 1. Uncharged particles. J Colloid Interface Sci 2013; 405:278-90. [DOI: 10.1016/j.jcis.2013.05.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/03/2013] [Accepted: 05/07/2013] [Indexed: 11/23/2022]
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25
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Danov KD, Stoyanov SD, Vitanov NK, Ivanov IB. Role of surfactants on the approaching velocity of two small emulsion drops. J Colloid Interface Sci 2012; 368:342-55. [DOI: 10.1016/j.jcis.2011.11.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 11/11/2011] [Accepted: 11/12/2011] [Indexed: 11/25/2022]
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26
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Interaction between like-charged particles at a liquid interface: Electrostatic repulsion vs. electrocapillary attraction. J Colloid Interface Sci 2010; 345:505-14. [DOI: 10.1016/j.jcis.2010.02.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 11/20/2022]
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27
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Danov KD, Kralchevsky PA. Capillary forces between particles at a liquid interface: general theoretical approach and interactions between capillary multipoles. Adv Colloid Interface Sci 2010; 154:91-103. [PMID: 20170895 DOI: 10.1016/j.cis.2010.01.010] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 01/18/2010] [Accepted: 01/28/2010] [Indexed: 11/16/2022]
Abstract
The liquid interface around an adsorbed colloidal particle can be undulated because of roughness or heterogeneity of the particle surface, or due to the fact that the particle has non-spherical (e.g. ellipsoidal or polyhedral) shape. In such case, the meniscus around the particle can be expanded in Fourier series, which is equivalent to a superposition of capillary multipoles, viz. capillary charges, dipoles, quadrupoles, etc. The capillary multipoles attract a growing interest because their interactions have been found to influence the self-assembly of particles at liquid interfaces, as well as the interfacial rheology and the properties of particle-stabilized emulsions and foams. As a rule, the interfacial deformation in the middle between two adsorbed colloidal particles is small. This fact is utilized for derivation of accurate asymptotic expressions for calculating the capillary forces by integration in the midplane, where the Young-Laplace equation can be linearized and the superposition approximation can be applied. Thus, we derived a general integral expression for the capillary force, which was further applied to obtain convenient asymptotic formulas for the force and energy of interaction between capillary multipoles of arbitrary orders. The new analytical expressions have a wider range of validity in comparison with the previously published ones. They are applicable not only for interparticle distances that are much smaller than the capillary length, but also for distances that are comparable or greater than the capillary length.
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Affiliation(s)
- Krassimir D Danov
- Department of Chemical Engineering, Faculty of Chemistry, University of Sofia, 1164 Sofia, Bulgaria
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28
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Templated assembly of polymer particles into mesoscopic clusters with well-defined configurations. Colloid Polym Sci 2010. [DOI: 10.1007/s00396-009-2169-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Boneva MP, Danov KD, Christov NC, Kralchevsky PA. Attraction between particles at a liquid interface due to the interplay of gravity- and electric-field-induced interfacial deformations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:9129-9139. [PMID: 19719220 DOI: 10.1021/la9006873] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In a previous study, we established that the attraction between electrically charged particles attached to a water/tetradecane interface is stronger than predicted on the basis of the gravity-induced lateral capillary force. Here, our goal is to explain this effect. The investigated particles are hydrophobized glass spheres of radii between 240 and 320 microm. Their weight is large enough to deform the liquid interface. The interfacial deformation is considerably greater for charged particles because of the electrodipping force that pushes the particles toward the water phase. By independent experiments with particles placed between two electrodes, we confirmed the presence of electric charges at the particle/tetradecane interface. The theoretical analysis shows that if the distribution of these surface charges is isotropic, the meniscus produced by the particle electric field decays too fast with distance and cannot explain the experimental observations. However, if the surface-charge distribution is anisotropic, it induces a saddle-shaped deformation in the liquid interface around each particle. This deformation, which is equivalent to a capillary quadrupole, decays relatively slow. Its interference with the gravity-induced isotropic meniscus around the other particle gives rise to a long-range attractive capillary force, F approximately 1/L3 (L=interparticle distance). The obtained agreement between the experimental and theoretical curves, and the reasonable values of the parameters determined from the fits, indicate that the observed stronger attraction in the investigated system can be really explained as a hybrid interaction between gravity-induced "capillary charges" and electric-field-induced "capillary quadrupoles".
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Affiliation(s)
- Mariana P Boneva
- Laboratory of Chemical Physics & Engineering, Faculty of Chemistry, Sofia University, 1164 Sofia, Bulgaria
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