1
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Liu Z. How Molecular Orientation Affects the Static Permittivity Profile of the Polar and Nonpolar Liquid-Liquid Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:15092-15098. [PMID: 39001873 DOI: 10.1021/acs.langmuir.4c01424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/15/2024]
Abstract
The dielectric permittivity across the liquid-liquid interface presents an intrinsic response, with respect to the instantaneous interface reference. We hypothesize that dielectric responses across the nonpolar and polar liquid-liquid interfaces have different behaviors and underlying mechanisms. Molecular dynamics simulations were used to compare and contrast the dielectric response of a nonpolar (1,2-dichloroethane/water) and a polar (1-octanol/water) liquid-liquid interface system. We found that the enhanced dielectric permittivity at the nonpolar interface is attributed to the increased water dipole orientation and polarization density. In the case of the polar interface, strong association of the immiscible solvents inhibits the molecular dipole orientation, counteracting the effect from the enhanced surface water polarization density and resulting in a standard dielectric response. Detailed knowledge of the hydrogen bond networks and molecular dipole orientation with respect to the specific instantaneous interfacial and bulk regions reveals the effect of molecular proximity and the interaction with the opposing interfacial molecules on the mechanism of the dielectric permittivity response across the liquid-liquid interface phase boundary.
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Affiliation(s)
- Zhu Liu
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310012, China
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518107, China
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2
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Li X, Liu Y, Zhao K. Aggregation Behavior of Ethoxylated Phytosterol Surfactants in Different Protic Solvents: An Insight from Dielectric Relaxation Studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1223-1231. [PMID: 38157320 DOI: 10.1021/acs.langmuir.3c02589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The micellar aggregation behavior of biocompatible surfactants, phytosterol ethoxylates (BPS-n, n is the oxyethylene (EO) chain length), containing polyoxyethylene chains in four organic solvents (glycerol (G), ethylene glycol (EG), formamide (FA), and N,N-dimethylformamide (DMF)) was studied by dielectric spectroscopy in the frequency range of 40 Hz to 110 MHz. Only the BPS-n/EG and BPS-n/G systems show distinct dielectric loss peaks near 104 Hz, indicating that BPS-n forms micellar aggregates in EG and G solvents, and the interfacial polarization (IP) between the aggregates and solvents leads to this relaxation. The dielectric spectra were analyzed based on the IP theory and a columnar dispersion model. The dielectric parameters of micelles, the permittivity and conductivity of micelles and solvents, and the volume fraction of the aggregates in solvents were calculated. On this basis, the binding numbers of each EO group on the hydrophobic chain to the solvent molecules EG and G were calculated to be 0.42 and 0.22, respectively. It was suggested that the aggregation appears to be related to the magnitude of the hydrogen bonding interactions. The lower number of EO group-binding solvents is because of the strong steric effect of alcohol solvents and the magnitude of the hydrogen bonding force.
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Affiliation(s)
- Xue Li
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Yuan Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Kongshuang Zhao
- College of Chemistry, Beijing Normal University, Beijing 100875, China
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3
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Krishnamurthy S, Ganapathy R, Sood AK. Overcoming power-efficiency tradeoff in a micro heat engine by engineered system-bath interactions. Nat Commun 2023; 14:6842. [PMID: 37891165 PMCID: PMC10611737 DOI: 10.1038/s41467-023-42350-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
All real heat engines, be it conventional macro engines or colloidal and atomic micro engines, inevitably tradeoff efficiency in their pursuit to maximize power. This basic postulate of finite-time thermodynamics has been the bane of all engine design for over two centuries and all optimal protocols implemented hitherto could at best minimize only the loss in the efficiency. The absence of a protocol that allows engines to overcome this limitation has prompted theoretical studies to suggest universality of the postulate in both passive and active engines. Here, we experimentally overcome the power-efficiency tradeoff in a colloidal Stirling engine by selectively reducing relaxation times over only the isochoric processes using system bath interactions generated by electrophoretic noise. Our approach opens a window of cycle times where the tradeoff is reversed and enables the engine to surpass even their quasistatic efficiency. Our strategies finally cut loose engine design from fundamental restrictions and pave way for the development of more efficient and powerful engines and devices.
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Affiliation(s)
| | - Rajesh Ganapathy
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- Sheikh Saqr Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - A K Sood
- Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India.
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4
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Liu Z, Jiang X, Li S, Chen J, Jiang C, Wang K, Zhang C, Wang B. A disposable impedance-based sensor for in-line cell growth monitoring in CAR-T cell manufacturing. Bioelectrochemistry 2023; 152:108416. [PMID: 37023618 DOI: 10.1016/j.bioelechem.2023.108416] [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: 11/22/2022] [Revised: 03/17/2023] [Accepted: 03/18/2023] [Indexed: 04/08/2023]
Abstract
This paper presents the development of low-cost, disposable impedance-based sensors for real-time, in-line monitoring of suspension cell culture. The sensors consist of electrical discharge machining (EDM) cut aluminum electrodes and polydimethylsiloxane (PDMS) spacers, both of which are low-cost materials that can be safely disposed of. Our research demonstrates the capability of these low-cost sensors for in-line, non-invasive monitoring of suspension cell growth in cell manufacturing. We use a hybrid equivalent circuit model to extract key features/parameters from intertwined impedance signals, which are then fed to a novel physics-inspired (gray-box) model designed for α-relaxation. This model determines viable cell count (VCC), a critical quality attribute (CQA) in cell manufacturing. Predicted VCC trends are then compared with image-based cell count data to verify their accuracy.
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Affiliation(s)
- Zhaonan Liu
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta 30332, United States
| | - Xuzhou Jiang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States
| | - Shuai Li
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States
| | - Jialei Chen
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta 30332, United States
| | - Chen Jiang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta 30332, United States
| | - Kan Wang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States
| | - Chuck Zhang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta 30332, United States.
| | - Ben Wang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta 30332, United States; H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta 30332, United States
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5
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Hoang Ngoc Minh T, Stoltz G, Rotenberg B. Frequency and field-dependent response of confined electrolytes from Brownian dynamics simulations. J Chem Phys 2023; 158:104103. [PMID: 36922117 DOI: 10.1063/5.0139258] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Using Brownian dynamics simulations, we investigate the effects of confinement, adsorption on surfaces, and ion-ion interactions on the response of confined electrolyte solutions to oscillating electric fields in the direction perpendicular to the confining walls. Nonequilibrium simulations allows to characterize the transitions between linear and nonlinear regimes when varying the magnitude and frequency of the applied field, but the linear response, characterized by the frequency-dependent conductivity, is more efficiently predicted from the equilibrium current fluctuations. To that end, we (rederive and) use the Green-Kubo relation appropriate for overdamped dynamics, which differs from the standard one for Newtonian or underdamped Langevin dynamics. This expression highlights the contributions of the underlying Brownian fluctuations and of the interactions of the particles between them and with external potentials. Although already known in the literature, this relation has rarely been used to date, beyond the static limit to determine the effective diffusion coefficient or the DC conductivity. The frequency-dependent conductivity always decays from a bulk-like behavior at high frequency to a vanishing conductivity at low frequency due to the confinement of the charge carriers by the walls. We discuss the characteristic features of the crossover between the two regimes, most importantly how the crossover frequency depends on the confining distance and the salt concentration, and the fact that adsorption on the walls may lead to significant changes both at high and low frequencies. Conversely, our results illustrate the possibility to obtain information on diffusion between walls, charge relaxation, and adsorption by analyzing the frequency-dependent conductivity.
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Affiliation(s)
- Thê Hoang Ngoc Minh
- CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, Sorbonne Université, F-75005 Paris, France
| | | | - Benjamin Rotenberg
- CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, Sorbonne Université, F-75005 Paris, France
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6
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Chai Z, Childress A, Busnaina AA. Directed Assembly of Nanomaterials for Making Nanoscale Devices and Structures: Mechanisms and Applications. ACS NANO 2022; 16:17641-17686. [PMID: 36269234 PMCID: PMC9706815 DOI: 10.1021/acsnano.2c07910] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/06/2022] [Indexed: 05/19/2023]
Abstract
Nanofabrication has been utilized to manufacture one-, two-, and three-dimensional functional nanostructures for applications such as electronics, sensors, and photonic devices. Although conventional silicon-based nanofabrication (top-down approach) has developed into a technique with extremely high precision and integration density, nanofabrication based on directed assembly (bottom-up approach) is attracting more interest recently owing to its low cost and the advantages of additive manufacturing. Directed assembly is a process that utilizes external fields to directly interact with nanoelements (nanoparticles, 2D nanomaterials, nanotubes, nanowires, etc.) and drive the nanoelements to site-selectively assemble in patterned areas on substrates to form functional structures. Directed assembly processes can be divided into four different categories depending on the external fields: electric field-directed assembly, fluidic flow-directed assembly, magnetic field-directed assembly, and optical field-directed assembly. In this review, we summarize recent progress utilizing these four processes and address how these directed assembly processes harness the external fields, the underlying mechanism of how the external fields interact with the nanoelements, and the advantages and drawbacks of utilizing each method. Finally, we discuss applications made using directed assembly and provide a perspective on the future developments and challenges.
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Affiliation(s)
- Zhimin Chai
- State
Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing100084, China
- NSF
Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing
(CHN), Northeastern University, Boston, Massachusetts02115, United States
| | - Anthony Childress
- NSF
Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing
(CHN), Northeastern University, Boston, Massachusetts02115, United States
| | - Ahmed A. Busnaina
- NSF
Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing
(CHN), Northeastern University, Boston, Massachusetts02115, United States
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7
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Kuznetcov I, Kantzas A, Bryant S. Dielectric spectroscopy of nanofluids in deionized water: Method of removing electrode polarization effect. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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8
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Lan JCW, Su CA, Chen YL, Ng HS. Application of AC-Impedance in microbial cultivation system for in-situ biomass measurements. J Taiwan Inst Chem Eng 2022. [DOI: 10.1016/j.jtice.2022.104405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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9
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Hidayah AN, Herbani Y, Steven E, Subhan A, Triyono D, Isnaeni, Suliyanti MM, Shiddiq M. Tuning the electrical properties of colloidal nanoalloys by varying their composition. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Renault C, Laborde C, Cossettini A, Selmi L, Widdershoven F, Lemay SG. Electrochemical characterization of individual oil micro-droplets by high-frequency nanocapacitor array imaging. Faraday Discuss 2021; 233:175-189. [PMID: 34904606 PMCID: PMC8981490 DOI: 10.1039/d1fd00044f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
CMOS-based nanocapacitor arrays allow local probing of the impedance of an electrolyte in real time and with sub-micron spatial resolution. Here we report on the physico-chemical characterization of individual microdroplets of oil in a continuous water phase using this new tool. We monitor the sedimentation and wetting dynamics of individual droplets, estimate their volume and infer their composition based on their dielectric constant. From measurements before and after wetting of the surface, we also attempt to estimate the contact angle of individual micron-sized droplets. These measurements illustrate the capabilities and versatility of nanocapacitor array technology.
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Affiliation(s)
- Christophe Renault
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. .,Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, IP Paris, Route de Saclay, Palaiseau, 91128, France
| | - Cecilia Laborde
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Andrea Cossettini
- Integrated Systems Laboratory, ETH Zürich, Gloriastrasse 35, 8092 Zürich, Switzerland.,DPIA, Università degli Studi di Udine, via delle Scienze 206, 33100 Udine, Italy
| | - Luca Selmi
- DIEF, University of Modena and Reggio Emilia, Via Vivarelli 10, Modena, 41125, Italy
| | - Frans Widdershoven
- NXP Semiconductors, Technology & Operations/CTO office, High Tech Campus 46, Eindhoven 5656 AE, The Netherlands
| | - Serge G Lemay
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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11
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Maenhout G, Markovic T, Nauwelaers B. Controlled Measurement Setup for Ultra-Wideband Dielectric Modeling of Muscle Tissue in 20-45 °C Temperature Range. SENSORS (BASEL, SWITZERLAND) 2021; 21:7644. [PMID: 34833716 PMCID: PMC8617941 DOI: 10.3390/s21227644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 11/21/2022]
Abstract
In order to design electromagnetic applicators for diagnostic and therapeutic applications, an adequate dielectric tissue model is required. In addition, tissue temperature will heavily influence the dielectric properties and the dielectric model should, thus, be extended to incorporate this temperature dependence. Thus, this work has a dual purpose. Given the influence of temperature, dehydration, and probe-to-tissue contact pressure on dielectric measurements, this work will initially present the first setup to actively control and monitor the temperature of the sample, the dehydration rate of the investigated sample, and the applied probe-to-tissue contact pressure. Secondly, this work measured the dielectric properties of porcine muscle in the 0.5-40 GHz frequency range for temperatures from 20 °C to 45 °C. Following measurements, a single-pole Cole-Cole model is presented, in which the five Cole-Cole parameters (ϵ∞, σs, Δϵ, τ, and α) are given by a first order polynomial as function of tissue temperature. The dielectric model closely agrees with the limited dielectric models known in literature for muscle tissue at 37 °C, which makes it suited for the design of in vivo applicators. Furthermore, the dielectric data at 41-45 °C is of great importance for the design of hyperthermia applicators.
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Affiliation(s)
- Gertjan Maenhout
- Division Telemic, Department of Electrical Engineering (ESAT), KU Leuven, Kasteelpark Arenberg 10, Box 2444, 3001 Leuven, Belgium or (T.M.); (B.N.)
| | - Tomislav Markovic
- Division Telemic, Department of Electrical Engineering (ESAT), KU Leuven, Kasteelpark Arenberg 10, Box 2444, 3001 Leuven, Belgium or (T.M.); (B.N.)
- Imec, Kapeldreef 75, 3001 Heverlee, Belgium
| | - Bart Nauwelaers
- Division Telemic, Department of Electrical Engineering (ESAT), KU Leuven, Kasteelpark Arenberg 10, Box 2444, 3001 Leuven, Belgium or (T.M.); (B.N.)
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12
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Habibi S, Joshi PU, Mi X, Heldt CL, Minerick AR. Changes in Membrane Dielectric Properties of Porcine Kidney Cells Provide Insight into the Antiviral Activity of Glycine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8344-8356. [PMID: 32614601 DOI: 10.1021/acs.langmuir.0c00175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to monitor the status and progression of viral infections is important for development and screening of new antiviral drugs. Previous research illustrated that the osmolyte glycine (Gly) reduced porcine parvovirus (PPV) infection in porcine kidney (PK-13) cells by stabilizing the capsid protein and preventing virus capsid assembly into viable virus particles. Dielectrophoresis (DEP) was examined herein as a noninvasive, electric field- and frequency-dependent tool for real-time monitoring of PK-13 cell responses to obtain information about membrane barrier functionality and polarization. DEP responses of PK-13 cells were compared to those of PPV-infected cells in the absence and presence of the osmolyte glycine. With infection progression, PK-13 DEP spectra shifted toward lower frequencies, reducing crossover frequencies (fCO). The spherical single-shell model was used to extract PK-13 cell dielectric properties. Upon PPV infection, specific membrane capacitance increased over the time progression of virus attachment, penetration, and capsid protein production and assembly. Following glycine treatment, the DEP spectra displayed attenuated fCO and specific membrane capacitance values shifted back toward uninfected PK-13 cell values. These results suggest that DEP can be used to noninvasively monitor the viral infection cycle and screen antiviral compounds. DEP can augment traditional tools by elucidating membrane polarization changes related to drug mechanisms that interrupt the virus infection cycle.
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Affiliation(s)
- Sanaz Habibi
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Pratik U Joshi
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Xue Mi
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Caryn L Heldt
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Adrienne R Minerick
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
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13
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Khandelwal AV, Singh A, Pal N, Kumar R, Goel G, Gupta S. AC Conductivity Measurements of Ultradilute Colloidal Suspensions in HEPES Buffer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14725-14733. [PMID: 31626736 DOI: 10.1021/acs.langmuir.9b01464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Impedance spectroscopy was used to probe the AC conductivity of extremely dilute colloidal suspensions (2.5 × 10-5 ≤ Φw/v ≤ 4.0 × 10-2) comprising of polystyrene microspheres (PS; κa ≫ 1 and ζ = -65 mV), gold nanoparticles (Au NPs; κa > 1 and ζ = -26 mV), and Au-coated PS metallodielectric particles (Au-PS) in HEPES buffer. When AC electric fields of strength 10 mV and 1 MHz were applied via 100 μm gap interdigitated microelectrodes across 10 μL samples, a highly resistive (θcapacitive < 1°) and nonmonotonic response was obtained with particle concentrations at steady state. While the suspensions were less resistive (than the buffer) below a critical concentration, they became more resistive above it. More interestingly, particle-particle interactions took place in suspensions with concentrations as low as 0.005% w/v. We believe this unique behavior is linked to the ion size asymmetry in the HEPES molecule that provides an ideal microenvironment for counterionic polarization around the particles. The exact mechanism of polarization in HEPES, however, still remains elusive as the current theoretical models for simple electrolytes fail to explain our data.
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Affiliation(s)
- Aditya Vikram Khandelwal
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Akash Singh
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Namrata Pal
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Rajdeep Kumar
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Gaurav Goel
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Shalini Gupta
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
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14
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O'Brien RW. Time-dependent electrokinetic processes in porous colloidal particles. J Colloid Interface Sci 2019; 555:254-267. [DOI: 10.1016/j.jcis.2019.07.074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 11/16/2022]
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15
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Chen SH, Singer SJ. Molecular Dynamics Study of the Electric Double Layer and Nonlinear Spectroscopy at the Amorphous Silica–Water Interface. J Phys Chem B 2019; 123:6364-6384. [DOI: 10.1021/acs.jpcb.9b05871] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Si-Han Chen
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sherwin J. Singer
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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16
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Hashemi Amrei SMH, Miller GH, Ristenpart WD. Asymmetric rectified electric fields between parallel electrodes: Numerical and scaling analyses. Phys Rev E 2019; 99:062603. [PMID: 31330682 DOI: 10.1103/physreve.99.062603] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Indexed: 06/10/2023]
Abstract
Recent computational and experimental work has established the existence of asymmetric rectified electric fields (AREFs), a type of steady electric field that occurs in liquids in response to an applied oscillatory potential, provided the ions present have different mobilities [Hashemi Amrei et al., Phys. Rev. Lett. 121, 185504 (2018)PRLTAO0031-900710.1103/PhysRevLett.121.185504]. Here we use scaling analyses and numerical calculations to elaborate the nature of one-dimensional AREFs between parallel electrodes. The AREF magnitude is shown to increase quadratically with applied potential at low potentials, increase nonlinearly at intermediate potentials, then increase with a constant rate slower than quadratically at sufficiently high potentials, with no impact at any potential on the spatial structure of the AREF. In contrast, the AREF peak location increases linearly with a frequency-dependent diffusive length scale for all conditions tested, with corresponding decreases in both the magnitude and number of sign changes in the directionality of AREF. Furthermore, both the magnitude and spatial structure of the AREF depend sensitively on the ionic mobilities, valencies, and concentrations, with a potential-dependent peak AREF magnitude occurring at an ionic mobility ratio of D_{-}/D_{+}⪅5. The results are summarized with approximate scaling expressions that will facilitate interpretation of the steady component for oscillatory fields in liquid systems.
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Affiliation(s)
- S M H Hashemi Amrei
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
| | - Gregory H Miller
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
| | - William D Ristenpart
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
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17
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Kang KK, Lee B, Lee CS. Recent progress in the synthesis of inorganic particulate materials using microfluidics. J Taiwan Inst Chem Eng 2019. [DOI: 10.1016/j.jtice.2018.08.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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Hashemi Amrei SMH, Bukosky SC, Rader SP, Ristenpart WD, Miller GH. Oscillating Electric Fields in Liquids Create a Long-Range Steady Field. PHYSICAL REVIEW LETTERS 2018; 121:185504. [PMID: 30444382 DOI: 10.1103/physrevlett.121.185504] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/19/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate that application of an oscillatory electric field to a liquid yields a long-range steady field, provided the ions present have unequal mobilities. The main physics is illustrated by a two-ion harmonic oscillator, yielding an asymmetric rectified field whose time average scales as the square of the applied field strength. Computations of the fully nonlinear electrokinetic model corroborate the two-ion model and further demonstrate that steady fields extend over large distances between two electrodes. Experimental measurements of the levitation height of micron-scale colloids versus applied frequency accord with the numerical predictions. The heretofore unsuspected existence of a long-range steady field helps explain several long-standing questions regarding the behavior of particles and electrically induced fluid flows in response to oscillatory potentials.
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Affiliation(s)
- S M H Hashemi Amrei
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
| | - Scott C Bukosky
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
| | - Sean P Rader
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
| | - William D Ristenpart
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
| | - Gregory H Miller
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, USA
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19
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Khademi M, Barz DPJ. Dielectric relaxation spectroscopy of aqueous micellar electrolyte solutions: A novel application to infer Dukhin number and zeta potential of a micelle. Electrophoresis 2018; 40:710-719. [DOI: 10.1002/elps.201800293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/14/2018] [Accepted: 08/29/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Mahmoud Khademi
- Department of Chemical Engineering; Queen's University; Kingston Ontario Canada
| | - Dominik P. J. Barz
- Department of Chemical Engineering; Queen's University; Kingston Ontario Canada
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20
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Li W, Wang J, Yang M, Zhao K. Dielectric Behavior and Phase Behavior of Block Copolymer PEO 13-PPO 30-PEO 13 Aqueous Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5574-5580. [PMID: 29694785 DOI: 10.1021/acs.langmuir.8b00776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dielectric spectroscopy can be applied to study the structure and dynamics of block polymer. In this work, dielectric measurements of block copolymer Pluronic L64 solution are carried out in the frequency range between 40 Hz and 110 MHz with variable temperatures and concentrations. We analyze the phase behavior of the PEO13-PPO30-PEO13 (Pluronic L64) aqueous system according to the concentration/temperature-dependence of direct current conductivity. The result indicates the sensitivity of the phase behavior and conductivity of the Pluronic L64 solution to temperature. Besides, two relaxations were observed: relaxation 1 (0.5 MHz) is related to the gelation process, while relaxation 2 (5 MHz) is caused by the interface polarization. On the basis of relaxation 2, the volume fraction and permittivity of the particle were calculated. The formations of the block copolymer micelle and gel are monitored successfully by the temperature/concentration-dependence of the dielectric parameters and the volume fraction.
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Affiliation(s)
- Wantong Li
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Juan Wang
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Man Yang
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Kongshuang Zhao
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
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21
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Membrane electroporation: chemical thermodynamics and flux kinetics revisited and refined. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 47:373-387. [DOI: 10.1007/s00249-018-1305-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 03/24/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022]
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22
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Aravopoulou D, Kyriakos K, Miasnikova A, Laschewsky A, Papadakis CM, Kyritsis A. Comparative Investigation of the Thermoresponsive Behavior of Two Diblock Copolymers Comprising PNIPAM and PMDEGA Blocks. J Phys Chem B 2018; 122:2655-2668. [DOI: 10.1021/acs.jpcb.7b09647] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Dionysia Aravopoulou
- Physics Department, National Technical University of Athens, Iroon Polytechneiou 9, Zografou Campus, Athens 15780, Greece
| | - Konstantinos Kyriakos
- Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Anna Miasnikova
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - André Laschewsky
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
- Fraunhofer Institut für Angewandte Polymerforschung, Geiselbergstr. 69, 14476 Potsdam-Golm, Germany
| | - Christine M. Papadakis
- Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Apostolos Kyritsis
- Physics Department, National Technical University of Athens, Iroon Polytechneiou 9, Zografou Campus, Athens 15780, Greece
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23
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24
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Dielectric spectroscopy of granular material in an electrolyte solution of any ionic strength. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.07.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Leroy P, Weigand M, Mériguet G, Zimmermann E, Tournassat C, Fagerlund F, Kemna A, Huisman JA. Spectral induced polarization of Na-montmorillonite dispersions. J Colloid Interface Sci 2017; 505:1093-1110. [DOI: 10.1016/j.jcis.2017.06.071] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 05/27/2017] [Accepted: 06/20/2017] [Indexed: 11/25/2022]
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26
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Wang S, Zhao K. Insight into the structure of oppositely charged surfactant–polymer system by dielectric spectroscopy. Colloid Polym Sci 2017. [DOI: 10.1007/s00396-017-4180-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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27
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Sasaki K, Mizuno M, Wake K, Watanabe S. Monte Carlo simulations of skin exposure to electromagnetic field from 10 GHz to 1 THz. Phys Med Biol 2017; 62:6993-7010. [PMID: 28742056 DOI: 10.1088/1361-6560/aa81fc] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study, we present an assessment of human-body exposure to an electromagnetic field at frequencies ranging from 10 GHz to 1 THz. The energy absorption and temperature elevation were assessed by solving boundary value problems of the one-dimensional Maxwell equations and a bioheat equation for a multilayer plane model. Dielectric properties were measured [Formula: see text] at frequencies of up to 1 THz at body temperature. A Monte Carlo simulation was conducted to assess variations of the transmittance into a skin surface and temperature elevation inside a body by considering the variation of the tissue thickness due to individual differences among human bodies. Furthermore, the impact of the dielectric properties of adipose tissue on temperature elevation, for which large discrepancies between our present measurement results and those in past works were observed, was also examined. We found that the dielectric properties of adipose tissue do not impact on temperature elevation at frequencies over 30 GHz. The potential risk of skin burn was discussed on the basis of the temperature elevation in millimeter-wave and terahertz-wave exposure. Furthermore, the consistency of the basic restrictions in the international guidelines set by ICNIRP was discussed.
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Affiliation(s)
- Kensuke Sasaki
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
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28
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Guo X, Zhao K. Dielectric analysis based on spherical-shell model for cationic and anionic spherical polyelectrolyte brushes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:295101. [PMID: 28513474 DOI: 10.1088/1361-648x/aa73c4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report here a dielectric study on cationic and anionic spherical polyelectrolyte brush (SPB) (consisting of a polystyrene (PS) core and poly (2-aminoethylmethacrylate hydrochloride (PAEMH) chains or poly (acrylic acid) (PAA) chains grafted onto the core) suspensions over a frequency range of 40 Hz-110 MHz. The relaxation behavior of the suspensions shows significant changes in the brush layer properties when changing the particle mass fraction or pH of the system. After eliminating the electrode polarization effect at a low frequency, two definite relaxations related to interfacial polarization, around 100 kHz and 10 MHz respectively, are observed. Based on a single layer spherical-shell model, we developed a curve-fitting procedure to analyze such dielectric spectra for soft particles, and then calculated the dielectric properties of the components of the SPBs (such as the permittivities and conductivities of the layer and solution phase), especially the layer thickness d s of the polyelectrolyte chain (PE) layer. We also found a larger confinement degree of counterions in the PAEMH brush due to the protonation of the amino group. Moreover, the repulsive force between the SPB particles is evaluated by using the d s combined with the relative theoretical formulas. We conclude that by raising (reducing) the acidity of the system, the stability of the PAEMH-SPB (PAA-SPB) suspension was improved. An increase in particle concentration can also improve the stability of these two dispersions.
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Affiliation(s)
- Xiaoxia Guo
- College of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China
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29
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Guo X, Zhao K. Insight into the electrical properties and chain conformation of spherical polyelectrolyte brushes by dielectric spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:055102. [PMID: 27941218 DOI: 10.1088/1361-648x/29/5/055102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report here a dielectric study on three kinds of anionic spherical polyelectrolyte brush (SPBs, consisting of a polystyrene (PS) core and three different poly (acrylic acid) chains grafted onto the core) suspensions over a frequency ranging from 40 Hz to 110 MHz. The relaxation behavior of the SPB suspensions shows significant changes in the brush-layer properties when the mass fraction of SPBs and the pH of the suspensions change. Two definite relaxations related to the interfacial polarization are observed around 100 kHz and 10 MHz. A single-layer spherical-shell model is applied to describe the SPB suspensions wherein the suspended SPB is modeled as a spherical-shell composite particle in which an insulated PS sphere is surrounded by a conducting ion-permeable shell (the polyelectrolyte chain layer). We developed the curve-fitting procedure to analyze the dielectric spectrum in order to obtain the dielectric properties of the components of the SPBs, especially the properties of the polyelectrolyte brush. Based on this method and model, the permittivity and conductivity of the brush layer, ζ potential, etc are calculated. The ordered orientation of the water molecules in the layer leads to an additional electrical dipole moment; increasing pH causes the brush layer to swell. In addition, the repulsive force between the SPB particles are evaluated using the brush-layer thickness, which is obtained by fitting dielectric spectra, combined with relative theoretical formulas. Increasing PH values or SPB concentration would improve the stability of the SPBs dispersion.
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Affiliation(s)
- Xiaoxia Guo
- College of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China
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30
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Asymptotic behaviors of the Poisson-Nernst-Planck model, generalizations and best adjust of experimental data. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2016.12.075] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Heatley KL, Ma F, Wu N. Colloidal molecules assembled from binary spheres under an AC electric field. SOFT MATTER 2017; 13:436-444. [PMID: 27901539 DOI: 10.1039/c6sm02091g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Colloidal particles are envisioned as analogues of atoms and molecules, however they often lack the complexities present in their counterparts. In this work, we report the assembly of colloidal molecules from a binary mixture of polystyrene spheres (1, 1.6, 2, and 4 μm) under an alternating current electric field. The rich family of assembled oligomers typically consists of a large sphere that is closely surrounded by a number of smaller petal particles, driven by the dipolar attraction between large and small particles. In deionized water, the number of satellite particles, i.e., the coordination number increases with the increasing size ratio of the constituent particles. For a given size ratio, the coordination number decreases with the increasing frequency of the applied field. These trends have also been correctly captured by computing the electric energy of different oligomers based on induced dipolar and double-layer interactions. By suspending the particles in polyvinylpyrrolidone aqueous solution, we can further tune the bond length of the oligomers independent of their coordination numbers. The addition of polyvinylpyrrolidone also allows us to lock the assembled colloidal molecules so that they remain intact after the electric field is turned off. Our method provides a robust way to produce a family of colloidal molecules with well-defined geometry and high yield.
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Affiliation(s)
- Kelley Lynch Heatley
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, 80401, USA.
| | - Fuduo Ma
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, 27695, USA
| | - Ning Wu
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, 80401, USA.
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32
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Crassous JJ, Demirörs AF. Multiscale directed self-assembly of composite microgels in complex electric fields. SOFT MATTER 2016; 13:88-100. [PMID: 27906392 DOI: 10.1039/c6sm00857g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study explored the application of localized electric fields for reversible directed self-assembly of colloidal particles in 3 dimensions. Electric field microgradients, arising from the use of micro-patterned electrodes, were utilized to direct the localization and self-assembly of polarizable (charged) particles resulting from a combination of dielectrophoretic and multipolar forces. Deionized dispersions of spherical and ellipsoidal core-shell microgels were employed for investigating their assembly under an external alternating electric field. We demonstrated that the frequency of the field allowed for an exquisite control over the localization of the particles and their self-assembled structures near the electrodes. We extended this approach to concentrated binary dispersions consisting of polarizable and less polarizable composite microgels. Furthermore, we utilized the thermosensitivity of the microgels to adjust the effective volume fraction and the dynamics of the system, which provided the possibility to dynamically "solidify" the assembly of the field-responsive particles by a temperature quench from their initial fluid state into an arrested crystalline state. Reversible solidification enables us to re-write/reconstruct various 3 dimensional assemblies by varying the applied field frequency.
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Affiliation(s)
- Jérôme J Crassous
- Division of Physical Chemistry, Department of Chemistry, Lund University, 221 00 Lund, Sweden.
| | - Ahmet F Demirörs
- Complex Materials, Department of Materials, ETH Zürich, 8093 Zürich, Switzerland.
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33
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Mohanty PS, Nöjd S, Bergman MJ, Nägele G, Arrese-Igor S, Alegria A, Roa R, Schurtenberger P, Dhont JKG. Dielectric spectroscopy of ionic microgel suspensions. SOFT MATTER 2016; 12:9705-9727. [PMID: 27808335 DOI: 10.1039/c6sm01683a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The determination of the net charge and size of microgel particles as a function of their concentration, as well as the degree of association of ions to the microgel backbone, has been pursued in earlier studies mainly by scattering and rheology. These methods suffer from contributions due to inter-particle interactions that interfere with the characterization of single-particle properties. Here we introduce dielectric spectroscopy as an alternative experimental method to characterize microgel systems. The advantage of dielectric spectroscopy over other experimental methods is that the polarization due to mobile charges within a microgel particle is only weakly affected by inter-particle interactions. Apart from electrode polarization effects, experimental spectra on PNIPAM-co-AA [poly(N-isopropylacrylamide-co-acrylic acid)] ionic microgel particles suspended in de-ionized water exhibit three well-separated relaxation modes, which are due to the polarization of the mobile charges within the microgel particles, the diffuse double layer around the particles, and the polymer backbone. Expressions for the full frequency dependence of the electrode-polarization contribution to the measured dielectric response are derived, and a theory is proposed for the polarization resulting from the mobile charges within the microgel. Relaxation of the diffuse double layer is modeled within the realm of a cell model. The net charge and the size of the microgel particles are found to be strongly varying with concentration. A very small value of the diffusion coefficient of ions within the microgel is found, due to a large degree of chemical association of protons to the polymer backbone.
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Affiliation(s)
- P S Mohanty
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden and School of Applied Sciences, KIIT University, Bhubaneswar 751024, India
| | - S Nöjd
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - M J Bergman
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - G Nägele
- Institute of Complex Systems ICS-3, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany. and Heinrich-Heine Universität Düsseldorf, Department of Physics, D-40225 Düsseldorf, Germany and JARA-SOFT, 52425 Jülich, Germany
| | - S Arrese-Igor
- Centro de Física de Materiales (CSIC-UPV/EHU), Materials Physics Center, 20018 San Sebastián, Spain
| | - A Alegria
- Centro de Física de Materiales (CSIC-UPV/EHU), Materials Physics Center, 20018 San Sebastián, Spain and Universidad del País Vasco (UPV/EHU), Departamento de Física de Materiales, 20080 San Sebastián, Spain
| | - R Roa
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin, Germany
| | - P Schurtenberger
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - J K G Dhont
- Institute of Complex Systems ICS-3, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany. and Heinrich-Heine Universität Düsseldorf, Department of Physics, D-40225 Düsseldorf, Germany and JARA-SOFT, 52425 Jülich, Germany
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34
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Dielectric analysis of different spherical polyelectrolyte brushes: Influence of pH and mass fraction on movement of counterions and electrical properties for different SPBs. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.08.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Su W, Yang M, Zhao K, Ngai T. Influence of Charged Groups on the Structure of Microgel and Volume Phase Transition by Dielectric Analysis. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00809] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Wenjuan Su
- College
of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Man Yang
- College
of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Kongshuang Zhao
- College
of Chemistry, Beijing Normal University, Beijing 100875, China
| | - To Ngai
- Department
of Chemistry, The Chinese University of Hong Kong, Shatin, N. T. Hong Kong, China
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36
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Petrov M, Shilov V, Trusov A, Voitylov A, Vojtylov V. Electro-optic research of polarizability dispersion in aqueous polydisperse suspensions of nanodiamonds. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.05.087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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37
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Chassagne C, Dubois E, Jiménez ML, van der Ploeg JPM, van Turnhout J. Compensating for Electrode Polarization in Dielectric Spectroscopy Studies of Colloidal Suspensions: Theoretical Assessment of Existing Methods. Front Chem 2016; 4:30. [PMID: 27486575 PMCID: PMC4949231 DOI: 10.3389/fchem.2016.00030] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 06/17/2016] [Indexed: 11/13/2022] Open
Abstract
Dielectric spectroscopy can be used to determine the dipole moment of colloidal particles from which important interfacial electrokinetic properties, for instance their zeta potential, can be deduced. Unfortunately, dielectric spectroscopy measurements are hampered by electrode polarization (EP). In this article, we review several procedures to compensate for this effect. First EP in electrolyte solutions is described: the complex conductivity is derived as function of frequency, for two cell geometries (planar and cylindrical) with blocking electrodes. The corresponding equivalent circuit for the electrolyte solution is given for each geometry. This equivalent circuit model is extended to suspensions. The complex conductivity of a suspension, in the presence of EP, is then calculated from the impedance. Different methods for compensating for EP are critically assessed, with the help of the theoretical findings. Their limit of validity is given in terms of characteristic frequencies. We can identify with one of these frequencies the frequency range within which data uncorrected for EP may be used to assess the dipole moment of colloidal particles. In order to extract this dipole moment from the measured data, two methods are reviewed: one is based on the use of existing models for the complex conductivity of suspensions, the other is the logarithmic derivative method. An extension to multiple relaxations of the logarithmic derivative method is proposed.
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Affiliation(s)
- Claire Chassagne
- Environmental Fluid Mechanics, Faculty of Civil Engineering and Geosciences, Delft University of Technology Delft, Netherlands
| | - Emmanuelle Dubois
- Laboratoire PHENIX, Centre National de la Recherche Scientifique, Sorbonne Universités, UPMC Université Paris 06 Paris, France
| | - María L Jiménez
- Departamento de Física Aplicada, Universidad de Granada Granada, Spain
| | - J P M van der Ploeg
- Formerly affiliated with Leiden Institute of Chemistry, Leiden University RA Leiden, Netherlands
| | - Jan van Turnhout
- Department of Chemical Engineering, Delft University of Technology Delft, Netherlands
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38
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Blakey R, Morales-Partera A. Microwave dielectric spectroscopy – A versatile methodology for online, non-destructive food analysis, monitoring and process control. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.eaef.2016.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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39
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Wake K, Sasaki K, Watanabe S. Conductivities of epidermis, dermis, and subcutaneous tissue at intermediate frequencies. Phys Med Biol 2016; 61:4376-89. [DOI: 10.1088/0031-9155/61/12/4376] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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40
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Rinne KF, Schulz JCF, Netz RR. Impact of secondary structure and hydration water on the dielectric spectrum of poly-alanine and possible relation to the debate on slaved versus slaving water. J Chem Phys 2016; 142:215104. [PMID: 26049528 DOI: 10.1063/1.4921777] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using extensive molecular dynamics simulations of a single eight-residue alanine polypeptide in explicit water, we investigate the influence of α-helix formation on the dielectric spectrum. For this, we project long equilibrium trajectories into folded and unfolded states and thereby obtain dielectric spectra representative for disordered as well α-helical conformations without the need to change any other system parameter such as pH or temperature. The absorption spectrum in the α-helical state exhibits a feature in the sub-GHz range that is significantly stronger than in the unfolded state. As we show by an additional decomposition into peptide and water contributions, this slow dielectric mode, the relaxation time of which matches the independently determined peptide rotational relaxation time, is mostly caused by peptide polarization correlations, but also contains considerable contributions from peptide-water correlations. In contrast, the peptide spectral contribution shows no features in the GHz range where bulk water absorbs, not even in the peptide-water correlation part, we conclude that hydration water around Ala8 is more influenced by peptide polarization relaxation effects than the other way around. A further decomposition into water-self and water-collective polarization correlations shows that the dielectric response of hydration water is, in contrast to electrolyte solutions, retarded and that this retardation is mostly due to collective effects, the self relaxation of hydration water molecules is only slightly slowed down compared to bulk water. We find the dynamic peptide-water polarization cross correlations to be rather long-ranged and to extend more than one nanometer away from the peptide-water interface into the water hydration shell, in qualitative agreement with previous simulation studies and recent THz absorption experiments.
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Affiliation(s)
- Klaus F Rinne
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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41
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Experimental study on dielectric relaxation of SiO2 nano-particle suspensions for developing a particle characterization method based on electrical impedance spectroscopy. POWDER TECHNOL 2015. [DOI: 10.1016/j.powtec.2015.04.070] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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42
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Wu H, Zhao K. Dielectric Relaxation of Spherical Polyelectrolyte Brushes: Movement of Counterions and Electrical Properties of the Brush Layer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:8566-8576. [PMID: 26172222 DOI: 10.1021/acs.langmuir.5b01408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Dielectric behaviors of spherical polyelectrolyte brush (SPB) suspensions under various mass fractions of SPB and the pH of solution were investigated in a frequency range of 40 Hz to 110 MHz. The SPB consists of a polystyrene (PS) core grafted with poly(acrylic acid) (PAA) chains. Two unique relaxations were found at either about 10 kHz or 1-10 MHz, respectively, with the former due to the diffusion of counterions and the latter resulting from the interfacial polarization. Using dielectric parameters of two relaxations, we obtained information about the migration of counterion and the conformation of polyelectrolyte chains. The PAA chains are fully stretched when pH is about 8 under the domination of the equilibrium between the penetration and diffusion of counterions in the brushes. A dielectric model is proposed to describe the high-frequency relaxation, and the permittivity and conductivity of SPB and its volume fraction were also calculated on the basis of the model. The surface conductivity of SPB, the Donnan potential, and the fixed charge density in the brush layer were derived from these paramaters. The distribution of the Donnan potential was also simulated by using Poisson-Boltzmann equations, and the result is in accordance with these obtained on the basis of the dielectric model.
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Affiliation(s)
- Haiyan Wu
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Kongshuang Zhao
- College of Chemistry, Beijing Normal University, Beijing 100875, China
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43
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Sasaki K, Isimura Y, Fujii K, Wake K, Watanabe S, Kojima M, Suga R, Hashimoto O. Dielectric property measurement of ocular tissues up to 110 GHz using 1 mm coaxial sensor. Phys Med Biol 2015; 60:6273-88. [PMID: 26237580 DOI: 10.1088/0031-9155/60/16/6273] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Measurement of the dielectric properties of ocular tissues up to 110 GHz was performed by the coaxial probe method. A coaxial sensor was fabricated to allow the measurement of small amounts of biological tissues. Four-standard calibration was applied in the dielectric property measurement to obtain more accurate data than that obtained with conventional three-standard calibration, especially at high frequencies. Novel data of the dielectric properties of several ocular tissues are presented and compared with data from the de facto database.
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Affiliation(s)
- K Sasaki
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
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44
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González MA, Delgado ÁV, Rica RA, Jiménez ML, Ahualli S. Electric Permittivity and Dynamic Mobility of Dilute Suspensions of Platelike Gibbsite Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:7934-7942. [PMID: 26135978 DOI: 10.1021/acs.langmuir.5b01136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this work we discuss the electrokinetic evaluation of model platelike particles. By model particles we mean homogeneous and controlled size and shape. The electrokinetic analysis in such complex geometries cannot be limited to a single data point as in usual electrophoresis in constant (dc) fields. The information can be made much richer if alternating (ac) fields with a sufficiently wide range of frequencies are used. In this case, two techniques can be applied: one is the determination of the frequency spectrum of the electric permittivity or dielectric constant (low-frequency dielectric dispersion), and the other is the electroacoustics of suspensions and the determination of the frequency dispersion of the electrophoretic mobility (dynamic or ac mobility). In this work, these techniques are used with planar gibbsite (γ-Al(OH)3) particles, modeled as oblate spheroids with a small aspect ratio. As in other laminar minerals, a particular charge distribution, differing between edges and faces, gives rise to very peculiar electrokinetic behavior. It is found that pH 7 approximately separates two distinct field responses: below that pH the dielectric dispersion and dynamic mobility data are consistent with the existence of individual, highly charged platelets, with charge mainly originating on edge surfaces. At pH 4, a low-frequency relaxation is observed, which must originated from larger particles. It is suggested that these are individual ones bridged by negatively charged fiberlike structures, coming from the partial decomposition of gibbsite particles. On the other side of the measured pH spectrum, the overall charge of the particles is low, and this probably produces aggregates with a relatively large average size, with relaxation frequencies on the low side. This is confirmed by dynamic mobility data, showing that a coherent picture of the nanostructure can be reached by combining the two techniques.
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Affiliation(s)
- M Alejandro González
- Department of Applied Physics, School of Science, University of Granada, 18071 Granada, Spain
| | - Ángel V Delgado
- Department of Applied Physics, School of Science, University of Granada, 18071 Granada, Spain
| | - Raúl A Rica
- Department of Applied Physics, School of Science, University of Granada, 18071 Granada, Spain
| | - María L Jiménez
- Department of Applied Physics, School of Science, University of Granada, 18071 Granada, Spain
| | - Silvia Ahualli
- Department of Applied Physics, School of Science, University of Granada, 18071 Granada, Spain
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Cheng TL, Wen YH. Iterative spectral method for solving electrostatic or magnetostatic problems in complex and evolving heterostructures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:053307. [PMID: 26066279 DOI: 10.1103/physreve.91.053307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Indexed: 06/04/2023]
Abstract
Electrostatic or magnetostatic problems involving complex heterogeneity are nontrivial for modeling and simulation. Most existing numerical methods focus on sharp interface models and the computational cost increases with increasing complexity of the geometry. Here we develop an iterative spectral method, the bound charge successive approximation algorithm, to solve electrostatic or magnetostatic heterogeneity problems in the context of diffuse-interface modeling. As tests and verifications, this algorithm is applied to calculation of the depolarization factor of an ellipsoid, and simulation of random dielectric mixtures and the dielectophoretic motion of multiple particles. The algorithm shows excellent efficiency and the computational cost mainly depends on the permittivity or permeability contrast in the whole system, regardless of the complexity of the geometry. In particular, for evolving heterostructures the solution of bound charge in one time step can be used as input for the next, which could further significantly shorten the iteration (approximation) process, making it practical to simulate the long-range electrostatic or magnetostatic interaction in complex and evolving heterostructures.
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Affiliation(s)
- Tian-Le Cheng
- National Energy Technology Laboratory, 1450 Queen Ave S.W., Albany, Oregon 97321, USA
| | - You-Hai Wen
- National Energy Technology Laboratory, 1450 Queen Ave S.W., Albany, Oregon 97321, USA
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Zhang XL, Chen XD, Zhao QZ, Ding L. The research on the dispersion effect improvement for nano-copper in erythritol. ACTA ACUST UNITED AC 2015. [DOI: 10.1179/1432891715z.0000000001359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- X. L. Zhang
- Shanghai Maritime University, 1550 Harbour Avenue, Shanghai 201306, China
| | - X. D. Chen
- Shanghai Maritime University, 1550 Harbour Avenue, Shanghai 201306, China
| | - Q. Z. Zhao
- Shanghai Maritime University, 1550 Harbour Avenue, Shanghai 201306, China
| | - L. Ding
- Shanghai Maritime University, 1550 Harbour Avenue, Shanghai 201306, China
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Nisisako T, Ando T, Hatsuzawa T. Capillary-assisted fabrication of biconcave polymeric microlenses from microfluidic ternary emulsion droplets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:5116-5125. [PMID: 25123596 DOI: 10.1002/smll.201401269] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 07/15/2014] [Indexed: 06/03/2023]
Abstract
In this study, a simple capillary-based approach for producing biconcave polymeric microlenses with uniform size and shape from ternary emulsion droplets is presented. Monodisperse ternary emulsion droplets (0.6-4.0 nL) are produced which contain a photocurable segment of an acrylate monomer and two non-curable segments of silicone oil (SO) by using a microfluidic sheath-flowing droplet generator on a glass chip. The curvature radius of the interfaces separating the droplet segments, as well as the droplet size, and production rate can be flexibly varied by changing the flow conditions of the organic and aqueous phases. Subsequently, off-chip suspension photopolymerization yields non-spherical polymeric microparticles with two spherical concave surfaces templated by two SO segments at random positions. By ultraviolet light irradiation of ternary droplets with two SO segments trapped by the interior wall of a cylindrical microcapillary (internal diameter: 130 μm), biconcave microlenses can be produced with two spherical concave surfaces with a common lens axis. The produced lenses are suitable for use as optical diverging lenses.
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Affiliation(s)
- Takasi Nisisako
- Precision and Intelligence Laboratory, Tokyo Institute of Technology, R2-6, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
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Ramos MM, Perea R, Delgado AV, Arroyo FJ. Dielectric relaxation in concentrated nonaqueous colloidal suspensions. J Colloid Interface Sci 2014; 436:132-7. [PMID: 25268816 DOI: 10.1016/j.jcis.2014.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/04/2014] [Accepted: 09/08/2014] [Indexed: 11/29/2022]
Abstract
In this work we report on the permittivity of suspensions of elongated goethite particles in silicone oils of different viscosities. In spite of the low conductivity of the systems, the electrode polarization is significant. To correct this phenomenon, the procedure chosen is the one called logarithmic derivative of the real part of the permittivity, and it proves to efficiently reduce the effect of electrodes to the extent that the spectra of pure liquids are flat in the accessible frequency range (20 Hz-1 MHz). In our suspensions, we observe the presence of a dielectric relaxation for frequencies in the range 4-40 kHz. In principle, such relaxations might be ascribed to the Maxwell-Wagner (MW) polarization. However, it is found that both the characteristic frequency and the relaxation amplitude of the suspensions increase with volume fraction, something unexpected for an MW relaxation. Such discrepancy can be explained by considering the Frenkel-Trukhan model, which reproduces the Maxwell-Wagner results in conditions of thin electrical double layers (which it is not our case). An excellent agreement is found between our data and the model predictions, using only the particle surface charge as a parameter.
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Affiliation(s)
- M M Ramos
- Department of Physics, University of Jaén, 23071 Jaén, Spain
| | - R Perea
- Department of Physics, University of Jaén, 23071 Jaén, Spain
| | - A V Delgado
- Department of Applied Physics, University of Granada, 18071 Granada, Spain
| | - F J Arroyo
- Department of Physics, University of Jaén, 23071 Jaén, Spain.
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Su W, Zhao K, Wei J, Ngai T. Dielectric relaxations of poly(N-isopropylacrylamide) microgels near the volume phase transition temperature: impact of cross-linking density distribution on the volume phase transition. SOFT MATTER 2014; 10:8711-8723. [PMID: 25263641 DOI: 10.1039/c4sm01516a] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Dielectric relaxation behaviors of three types of thermally sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels with different cross-linking density distributions were investigated in a frequency range from 40 Hz to 110 MHz at temperatures from 15 °C to 55 °C. After eliminating the electrode polarization at low frequency, two remarkable relaxations were observed, one in the kHz frequency range and the other in the MHz range. The low-frequency relaxation is attributed to the counterion polarization in the whole measuring temperature range, while the relaxation at high-frequency is probably dominated by different polarization mechanisms depending on below or above the volume phase transition temperature (VPTT): it is considered as micro-Brownian motion of side groups of PNIPAM when T < VPTT and interfacial polarization when T > VPTT. The temperature dependence of the dielectric parameters for both the relaxations presents an abrupt change around 32.5 °C, indicating the occurrence of phase transition. Based on the analysis and discussion about the micro-Brownian motion of the side groups, a possible microstructure for the microgels before and after the collapse of PNIPAM was suggested. A dielectric model to describe the collapsing microgel suspension was proposed, from which the electrical and structural parameters of the suspension were calculated. The information on the internal structure and hydration dynamic behavior of microgels was obtained by using the thermodynamic parameters which were calculated based on the Eyring equation. Our results reveal that the spatial distribution of the cross-linking density distribution has almost no effect on the volume phase transition temperature, but markedly affects the swelling capacity of PNIPAM microgels at low temperatures.
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Affiliation(s)
- Wenjuan Su
- College of Chemistry, Beijing Normal University, Beijing 100875, China
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Mishchuk NA. Analytical solution of the Poisson–Boltzmann problem for two-layer spherical cell model. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2014.05.072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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