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Silvera Batista CA, Wang K, Blake H, Nwosu-Madueke V, Marbach S. Artificial chemotaxis under electrodiffusiophoresis. J Colloid Interface Sci 2025; 677:171-180. [PMID: 39142158 DOI: 10.1016/j.jcis.2024.08.004] [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: 04/16/2024] [Revised: 07/30/2024] [Accepted: 08/01/2024] [Indexed: 08/16/2024]
Abstract
HYPOTHESIS Through a large parameter space, electric fields can tune colloidal interactions and forces leading to diverse static and dynamical structures. So far, however, field-driven interactions have been limited to dipole-dipole and hydrodynamic contributions. Nonetheless, in this work, we propose that under the right conditions, electric fields can also induce interactions based on local chemical fields and diffusiophoretic flows. EXPERIMENTS Herein, we present a strategy to generate and measure 3D chemical gradients under electric fields. In this approach, faradaic reactions at electrodes induce global pH gradients that drive long-range transport through electrodiffusiophoresis. Simultaneously, the electric field induces local pH gradients by driving the particle's double layer far from equilibrium. FINDINGS As a result, while global pH gradients lead to 2D focusing away from electrodes, local pH gradients induce aggregation in the third dimension. Evidence points to a mechanism of interaction based on diffusiophoresis. Interparticle interactions display a strong dependence on surface chemistry, zeta potential and diameter of particles. Furthermore, pH gradients can be readily tuned by adjusting the voltage and frequency of the electric field. For large Péclet numbers, we observed a collective chemotactic-like collapse of particles. Remarkably, such collapse occurs without reactions at a particle's surface. By mixing particles with different sizes, we also demonstrate, through experiments and Brownian dynamics simulations, the emergence of non-reciprocal interactions, where small particles are more drawn towards large ones.
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Affiliation(s)
- Carlos A Silvera Batista
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, 37205, United States; Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, 37205, United States.
| | - Kun Wang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, 37205, United States
| | - Hannah Blake
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, 37205, United States
| | - Vivian Nwosu-Madueke
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, 37205, United States
| | - Sophie Marbach
- CNRS, Sorbonne Université, Physicochimie des Electrolytes et Nanosystèmes Interfaciaux, Paris, F-75005, France.
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2
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Bayati P, Mallory SA. Orbits, Spirals, and Trapped States: Dynamics of a Phoretic Janus Particle in a Radial Concentration Gradient. ACS NANO 2024; 18:23047-23057. [PMID: 39137334 DOI: 10.1021/acsnano.4c05076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
A long-standing goal in colloidal active matter is to understand how gradients in fuel concentration influence the motion of phoretic Janus particles. Here, we present a theoretical description of the motion of a spherical phoretic Janus particle in the presence of a radial gradient of the chemical solute driving self-propulsion. Radial gradients are a geometry relevant to many scenarios in active matter systems and naturally arise due to the presence of a point source or sink of fuel. We derive an analytical solution for the Janus particle's velocity and quantify the influence of the radial concentration gradient on the particle's trajectory. Compared to a phoretic Janus particle in a linear gradient in fuel concentration, we uncover a much richer set of dynamic behaviors including circular orbits and trapped stationary states. We identify the ratio of the phoretic mobilities between the two domains of the Janus particle as a central quantity in tuning their dynamics. Our results provide a path for developing optimum protocols for tuning the dynamics of phoretic Janus particles and mixing fluid at the microscale. In addition, this work suggests a method for quantifying the surface properties of phoretic Janus particles, which have proven to be challenging to probe experimentally.
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Affiliation(s)
- Parvin Bayati
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Stewart A Mallory
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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3
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Li L, Xue C, Chang Q, Ren X, Li N, Yang J, Hu S, Xu H. Polyelectrolyte Hydrogel-Functionalized Photothermal Sponge Enables Simultaneously Continuous Solar Desalination and Electricity Generation Without Salt Accumulation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2401171. [PMID: 38497304 DOI: 10.1002/adma.202401171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/10/2024] [Indexed: 03/19/2024]
Abstract
Technologies that can simultaneously generate electricity and desalinate seawater are highly attractive and required to meet the increasing global demand for power and clean water. Here, a bifunctional solar evaporator that features continuous electric generation in seawater without salt accumulation is developed by rational design of polyelectrolyte hydrogel-functionalized photothermal sponge. This evaporator not only exhibits an unprecedentedly high water evaporation rate of 3.53 kg m-2 h-1along with 98.6% solar energy conversion efficiency but can also uninterruptedly deliver a voltage output of 0.972 V and a current density of 172.38 µA cm-2 in high-concentration brine over a prolonged period under one sun irradiation. Many common electronic devices can be driven by simply connecting evaporator units in series or in parallel without any other auxiliaries. Different from the previously proposed power generation mechanism, this study reveals that the water-enabled proton concentration fields in intermediate water region can also induce an additional ion electric field in free water region containing solute, to further enhance electricity output. Given the low-cost materials, simple self-regeneration design, scalable fabrication processes, and stable performance, this work offers a promising strategy for addressing the shortages of clean water and sustainable electricity.
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Affiliation(s)
- Lin Li
- Research Group of New Energy Materials and Devices, State Key Laboratory of Coal and CBM Co-Mining, North University of China, Taiyuan, 030051, P. R. China
| | - Chaorui Xue
- Research Group of New Energy Materials and Devices, State Key Laboratory of Coal and CBM Co-Mining, North University of China, Taiyuan, 030051, P. R. China
| | - Qing Chang
- Research Group of New Energy Materials and Devices, State Key Laboratory of Coal and CBM Co-Mining, North University of China, Taiyuan, 030051, P. R. China
| | - Xiaohu Ren
- College of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, P. R. China
- Future Industries Institute, UniSA STEM, University of South Australia, Adelaide, South Australia, SA 5095, Australia
| | - Ning Li
- Research Group of New Energy Materials and Devices, State Key Laboratory of Coal and CBM Co-Mining, North University of China, Taiyuan, 030051, P. R. China
| | - Jinlong Yang
- Research Group of New Energy Materials and Devices, State Key Laboratory of Coal and CBM Co-Mining, North University of China, Taiyuan, 030051, P. R. China
- State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, P. R. China
| | - Shengliang Hu
- Research Group of New Energy Materials and Devices, State Key Laboratory of Coal and CBM Co-Mining, North University of China, Taiyuan, 030051, P. R. China
| | - Haolan Xu
- Future Industries Institute, UniSA STEM, University of South Australia, Adelaide, South Australia, SA 5095, Australia
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4
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Wang Z, Huang Y, Zhang T, Xu K, Liu X, Zhang A, Xu Y, Zhou X, Dai J, Jiang Z, Zhang G, Liu H, Xia BY. Unipolar Solution Flow in Calcium-Organic Frameworks for Seawater-Evaporation-Induced Electricity Generation. J Am Chem Soc 2024. [PMID: 38176108 DOI: 10.1021/jacs.3c13159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Seawater-flow- and -evaporation-induced electricity generation holds significant promise in advancing next-generation sustainable energy technologies. This method relies on the electrokinetic effect but faces substantial limitations when operating in a highly ion-concentrated environment, for example, natural seawater. We present herein a novel solution using calcium-based metal-organic frameworks (MOFs, C12H6Ca2O19·2H2O) for seawater-evaporation-induced electricity generation. Remarkably, Ca-MOFs show an open-circuit voltage of 0.4 V and a short-circuit current of 14 μA when immersed in seawater under natural conditions. Our experiments and simulations revealed that sodium (Na) ions selectively transport within sub-nanochannels of these synthetic superhydrophilic MOFs. This selective ion transport engenders a unipolar solution flow, which drives the electricity generation behavior in seawater. This work not only showcases an effective Ca-MOF for electricity generation through seawater flow/evaporation but also contributes significantly to our understanding of water-driven energy harvesting technologies and their potential applications beyond this specific context.
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Affiliation(s)
- Zhengyun Wang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Yuchen Huang
- Équipe Chimie Inorganique, ICCMO, Université Paris Saclay, 17 Av. des Sciences, Orsay 91400, France
| | - Tiansui Zhang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Kunqi Xu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Rd, Shanghai 200240, China
| | - Xiaoling Liu
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Airong Zhang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - You Xu
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Xue Zhou
- College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Rd, Wuhan 430072, China
| | - Jiawei Dai
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Zhineng Jiang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Guoan Zhang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Hongfang Liu
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
| | - Bao Yu Xia
- School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), 1037 Luoyu Rd, Wuhan 430074, China
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5
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Bae J, Seo S, Wu R, Kim T. Programmable and Pixelated Solute Concentration Fields Controlled by Three-Dimensionally Networked Microfluidic Source/Sink Arrays. ACS NANO 2023; 17:20273-20283. [PMID: 37830478 DOI: 10.1021/acsnano.3c06247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Membrane-integrated microfluidic platforms have played a pivotal role in understanding natural phenomena coupled with solute concentration gradients at the micro- and nanoscale, enabling on-chip microscopy in well-defined planar concentration fields. However, the standardized two-dimensional fabrication schemes in microfluidics have impeded the realization of more complex and diverse chemical environmental conditions due to the limited possible arrangements of source/sink conditions in a fluidic domain. In this study, we present a microfluidic platform with a three-dimensional microchannel network design, where discretized membranes can be integrated and individually controlled in a two-dimensional array format at any location within the entire quasi-two-dimensional solute concentration field. We elucidate the principles of the device to implement operations of the pixel-like sources/sinks and dynamically programmable control of various long-lasting solute concentration fields. Furthermore, we demonstrate the application of the generated solute concentration fields in manipulating the transport of micrometer or submicrometer particles with a high degree of freedom, surpassing conventionally available solute concentration fields. This work provides an experimental tool for investigating complex systems under high-order chemical environmental conditions, thereby facilitating the extensive development of higher-performance micro- and nanotechnologies.
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Affiliation(s)
- Juyeol Bae
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Sangjin Seo
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Ronghui Wu
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Taesung Kim
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
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6
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Dao C, Everts JC, Ravnik M, Tserkovnyak Y. Nematronics: Reciprocal Coupling between Ionic Currents and Nematic Dynamics. PHYSICAL REVIEW LETTERS 2023; 130:168102. [PMID: 37154639 DOI: 10.1103/physrevlett.130.168102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 03/31/2023] [Indexed: 05/10/2023]
Abstract
Adopting a spintronics-inspired approach, we study the reciprocal coupling between ionic charge currents and nematic texture dynamics in a uniaxial nematic electrolyte. Assuming quenched fluid dynamics, we develop equations of motion analogously to spin torque and spin pumping. Based on the principle of least dissipation of energy, we derive the adiabatic "nematic torque" exerted by ionic currents on the nematic director field as well as the reciprocal motive force on ions due to the orientational dynamics of the director. We discuss several simple examples that illustrate the potential functionality of this coupling. Furthermore, using our phenomenological framework, we propose a practical means to extract the coupling strength through impedance measurements on a nematic cell. Exploring further applications based on this physics could foster the development of nematronics-nematic iontronics.
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Affiliation(s)
- Chau Dao
- Department of Physics and Astronomy and Bhaumik Institute for Theoretical Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Jeffrey C Everts
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - 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
| | - Yaroslav Tserkovnyak
- Department of Physics and Astronomy and Bhaumik Institute for Theoretical Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
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7
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Raj RR, Shields CW, Gupta A. Two-dimensional diffusiophoretic colloidal banding: optimizing the spatial and temporal design of solute sinks and sources. SOFT MATTER 2023; 19:892-904. [PMID: 36648425 DOI: 10.1039/d2sm01549h] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Diffusiophoresis refers to the phenomenon where colloidal particles move in response to solute concentration gradients. Existing studies on diffusiophoresis, both experimental and theoretical, primarily focus on the movement of colloidal particles in response to one-dimensional solute gradients. In this work, we numerically investigate the impact of two-dimensional solute gradients on the distribution of colloidal particles, i.e., colloidal banding, induced via diffusiophoresis. The solute gradients are generated by spatially arranged sources and sinks that emit/absorb a time-dependent solute molar rate. First we study a dipole system, i.e., one source and one sink, and discover that interdipole diffusion and molar rate decay timescales dictate colloidal banding. At timescales shorter than the interdipole diffusion timescale, we observe a rapid enhancement in particle enrichment around the source due to repulsion from the sink. However, at timescales longer than the interdipole diffusion timescale, the source and sink screen each other, leading to a slower enhancement. If the solute molar rate decays at the timescale of interdipole diffusion, an optimal separation distance is obtained such that particle enrichment is maximized. We find that the partition coefficient of solute at the interface between the source and bulk strongly impacts the optimal separation distance. Surprisingly, the diffusivity ratio of solute in the source and bulk has a much weaker impact on the optimal dipole separation distance. We also examine an octupole configuration, i.e., four sinks and four sources, arranged in a circle, and demonstrate that the geometric arrangement that maximizes enrichment depends on the radius of the circle. If the radius of the circle is small, it is preferred to have sources and sinks arranged in an alternating fashion. However, if the radius of the circle is large, a consecutive arrangement of sources and sinks is optimal. Our numerical framework introduces a novel method for spatially and temporally designing the banded structure of colloidal particles in two dimensions using diffusiophoresis and opens up new avenues in a field that has primarily focused on one-dimensional solute gradients.
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Affiliation(s)
- Ritu R Raj
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303, USA.
| | - C Wyatt Shields
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303, USA.
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Ankur Gupta
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303, USA.
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8
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Domínguez A, Popescu MN. A fresh view on phoresis and self-phoresis. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101610] [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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9
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Wang K, Behdani B, Silvera Batista CA. Visualization of Concentration Gradients and Colloidal Dynamics under Electrodiffusiophoresis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5663-5673. [PMID: 35467877 DOI: 10.1021/acs.langmuir.2c00252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this work, we present an experimental study of the dynamics of charged colloids under direct currents and gradients of chemical species (electrodiffusiophoresis). In our approach, we simultaneously visualize the development of concentration polarization and the ensuing dynamics of charged colloids near electrodes. With the aid of confocal microscopy and fluorescent probes, we show that the passage of current through water confined between electrodes, separated about a hundred microns, results in significant pH gradients. Depending on the current density and initial conditions, steep pH gradients develop, thus becoming a significant factor in the behavior of charged colloids. Furthermore, we show that steep pH gradients induce the focusing of charged colloids away from both electrodes. Our results provide the experimental basis for further development of models of electrodiffusiophoresis and the design of non-equilibrium strategies for the fabrication of advanced materials.
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Affiliation(s)
- Kun Wang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Behrouz Behdani
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Carlos A Silvera Batista
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
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Zavarzin SV, Kolesnikov AL, Budkov YA, Barash LY. Influence of fluid flows on electric double layers in evaporating colloidal sessile droplets. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2022; 45:24. [PMID: 35288808 DOI: 10.1140/epje/s10189-022-00178-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
A model is developed for describing the transport of charged colloidal particles in an evaporating sessile droplet on the electrified metal substrate in the presence of a solvent flow. The model takes into account the electric charge of colloidal particles and small ions produced by electrolytic dissociation of the active groups on the colloidal particles and solvent molecules. We employ a system of self-consistent Poisson and Nernst-Planck equations for electric potential and average concentrations of colloidal particles and ions with the appropriate boundary conditions. The fluid dynamics, temperature distribution and evaporation process are described with the Navier-Stokes equations, equations of heat conduction and vapor diffusion in air, respectively. The developed model is used to carry out a first-principles numerical simulation of charged silica colloidal particle transport in an evaporating aqueous droplet. We find that electric double layers can be destroyed by a sufficiently strong fluid flow.
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Affiliation(s)
- Semen V Zavarzin
- School of Applied Mathematics, HSE University, Moscow, Russia, 101000
| | - Andrei L Kolesnikov
- Institut für Nichtklassische Chemie e.V., Permoserstr. 15, Leipzig, 04318, Germany
| | - Yury A Budkov
- School of Applied Mathematics, HSE University, Moscow, Russia, 101000
- Landau Institute for Theoretical Physics, Chernogolovka, Russia, 142432
| | - Lev Yu Barash
- Landau Institute for Theoretical Physics, Chernogolovka, Russia, 142432.
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11
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Axial Motion Characterization of a Helical Ionic Polymer Metal Composite Actuator and Its Application in 3-DOF Micro-Parallel Platforms. ACTUATORS 2021. [DOI: 10.3390/act10100248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this work, a helical ionic polymer metal composite (IPMC) was fabricated by thermal treatment in a mold with helix grooves. The axial actuation behaviors of the helical IPMC actuator were observed, and the electromechanical and electrochemical characteristics were evaluated. The experimental results showed that as the voltage increased and the frequency decreased, the axial displacement, axial force, and electric current of the actuator all increased. Compared with square wave and sinusoidal signals, the actuator exhibited the most satisfactory motion under the direct current (DC) signal. For the electrochemical test, as the scanning rate decreased, the gravimetric specific capacitance increased. Within a suitable voltage range, the actuator was chemically stable. In addition, we coupled the Electrostatics module, Transport of Diluted Species module, and Solid Mechanics module in COMSOL Multiphysics software to model and analyze the helical IPMC actuator. The simulation data obtained were in good agreement with the experimental data. Finally, by using three helical IPMC actuators as driving components, an innovative three-degree-of-freedom (3-DOF) micro-parallel platform was designed, and it could realize a complex coupling movement of pitch, roll, and yaw under the action of an electric field. This platform is expected to be used in micro-assembly, flexible robots, and other fields.
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