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Fu Y, Wang S, Wan Z, Tian Y, Wang D, Ma Y, Yang L, Wei Z. Functional magnetic alginate/gelatin sponge-based flexible sensor with multi-mode response and discrimination detection properties for human motion monitoring. Carbohydr Polym 2024; 324:121520. [PMID: 37985056 DOI: 10.1016/j.carbpol.2023.121520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/01/2023] [Accepted: 10/19/2023] [Indexed: 11/22/2023]
Abstract
The functional flexible sensors that can simultaneously detect multiple external excitations have exhibited great potential in the human-machine interaction and wearable electronics. However, it is still a primary challenge to develop a multi-mode sensor that can achieve sensitivity equilibrium towards different stimuli, and effectively recognize external stimulus while in a facile and cost-effective material and methodology. This study presented a functional flexible sensor based on natural polymer sodium alginate and gelatin sponge electrode which could detect both external mechanical and magnetic stimuli with superiorities of outstanding sensing capability and stability. With the optimal multilayered structure, it possessed high magnetic responsive sensitivity of 0.45 T-1, excellent stability and recoverability. Its electrical property variations also displayed high sensitivity and durability under cyclic stretching, bending and compressing stimuli for 1000 cycles. More importantly, the sensor could not only respond to magnetic field and compression stimuli with contrary electrical responses, but also recognize the respective input signals to decouple different stimuli in real time. Furthermore, it was developed as electronic skins and smart sensor arrays for human physiological signals and mechanical-magnetic detection. Based on excellent multifunctional response characteristics, the sensor showed significant potential in next-generation intelligent multifunctional electronic system and artificial intelligence.
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Affiliation(s)
- Yu Fu
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, PR China; School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, PR China
| | - Shuangkun Wang
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Zhenshuai Wan
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Ye Tian
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, PR China.
| | - Dong Wang
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Yuelong Ma
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Liuhua Yang
- School of Civil and Engineering, Henan Polytechnic University, Jiaozuo 454000, PR China
| | - Zunghang Wei
- School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, PR China.
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2
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Messina R, Kemgang E. The relevance of curvature-induced quadrupolar interactions in dipolar chain aggregation. J Chem Phys 2023; 159:174903. [PMID: 37916594 DOI: 10.1063/5.0164168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/14/2023] [Indexed: 11/03/2023] Open
Abstract
The aggregation of dipolar chains driven by thermal fluctuations in an external strong (electric or magnetic) field is investigated theoretically. We discover a new simple electrostatic mechanism that rationalizes the counter-intuitive lateral coalescence of dipolar chains. There, we first demonstrate that two bent dipolar chains can either attract or repel each other depending if they possess similar or opposite curvatures, respectively. Upon bending, dipolar chains become the siege of polarization-induced local charges that in turn lead to quadrupolar couplings. This striking feature is then exploited to understand our conducted Monte Carlo simulations at finite temperature where thermal fluctuations cause local curvatures in the formed dipolar chains. The related quadrupolar attractive mode with correlated chain-curvatures is clearly identified in the simulation snapshots. Our findings shed new light on a longstanding problem in soft matter and related areas.
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Affiliation(s)
- René Messina
- Laboratoire de Physique et Chimie Théoriques, LPCT-UMR CNRS 7019, Université de Lorraine, 1 Boulevard Arago, 57070 Metz, France
| | - Ebenezer Kemgang
- Laboratoire de Physique et Chimie Théoriques, LPCT-UMR CNRS 7019, Université de Lorraine, 1 Boulevard Arago, 57070 Metz, France
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3
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Vinod S, Philip J. Thermal and rheological properties of magnetic nanofluids: Recent advances and future directions. Adv Colloid Interface Sci 2022; 307:102729. [PMID: 35834910 DOI: 10.1016/j.cis.2022.102729] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/27/2022] [Accepted: 07/03/2022] [Indexed: 01/14/2023]
Abstract
Technological advancement and miniaturization of electronic gadgets fueled intense research on nanofluids as potential candidates for cooling applications as a substitute to conventional heat transfer fluids. Among nanofluids, magnetic nanofluids, traditionally known as ferrofluids have attracted a lot of attention owing to their magnetic field tunable thermal conductivity and rheological properties due to the aggregation of the magnetic nanoparticles into chains or columns in the presence of the magnetic field. The field-induced aggregates act as low resistance pathways thereby improving thermal transport substantially. Recent studies show that ferrofluids with smaller size and narrow size distribution display significant enhancement in thermal conductivity in the presence of a magnetic field with negligible viscosity enhancement, which is ideal for effective thermal management of electronic devices, especially in miniature electronic devices. On the contrary, highly polydisperse ferrofluids containing large aggregates, show modest enhancement in thermal conductivity in the presence of a magnetic field and a huge enhancement in viscosity. The most recent studies show that magnetic field ramp rate has a profound effect on aggregation kinetics and thermal and rheological properties. The viscosity enhancement under an external stimulus impedes their practical use in electronics cooling, which warrants the need to attain a high thermal conductivity to viscosity ratio, under a modest magnetic field. Though there are several reviews on heat transfer in nanofluids and hybrid nanofluids, a comprehensive review on fundamental understanding of field-induced thermal and rheological properties in magnetic fluids is missing in the literature. This review provides a pedagogical description of the fundamental understanding of field-induced thermal and rheological properties in magnetic fluids, with the necessary background, key concepts, definitions, mechanisms, theoretical models, experimental protocols, and design of experiments. Many important case studies are presented along with the experimental design aspects. The review also provides a summary of important experimental studies with key findings, along with the key challenges and future research directions. The review is an ideal material for experimentalists and theoreticians practicing in the field of magnetic fluids, and also serves as an excellent reference for freshers who indent to begin research on this topic.
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Affiliation(s)
- Sithara Vinod
- Smart Materials Section, Corrosion Science and Technology Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India; Homi Bhabha National Institute, Mumbai, India
| | - John Philip
- Smart Materials Section, Corrosion Science and Technology Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India; Homi Bhabha National Institute, Mumbai, India.
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4
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Socoliuc V, Avdeev MV, Kuncser V, Turcu R, Tombácz E, Vékás L. Ferrofluids and bio-ferrofluids: looking back and stepping forward. NANOSCALE 2022; 14:4786-4886. [PMID: 35297919 DOI: 10.1039/d1nr05841j] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ferrofluids investigated along for about five decades are ultrastable colloidal suspensions of magnetic nanoparticles, which manifest simultaneously fluid and magnetic properties. Their magnetically controllable and tunable feature proved to be from the beginning an extremely fertile ground for a wide range of engineering applications. More recently, biocompatible ferrofluids attracted huge interest and produced a considerable increase of the applicative potential in nanomedicine, biotechnology and environmental protection. This paper offers a brief overview of the most relevant early results and a comprehensive description of recent achievements in ferrofluid synthesis, advanced characterization, as well as the governing equations of ferrohydrodynamics, the most important interfacial phenomena and the flow properties. Finally, it provides an overview of recent advances in tunable and adaptive multifunctional materials derived from ferrofluids and a detailed presentation of the recent progress of applications in the field of sensors and actuators, ferrofluid-driven assembly and manipulation, droplet technology, including droplet generation and control, mechanical actuation, liquid computing and robotics.
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Affiliation(s)
- V Socoliuc
- Romanian Academy - Timisoara Branch, Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Mihai Viteazu Ave. 24, 300223 Timisoara, Romania.
| | - M V Avdeev
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie Str. 6, 141980 Dubna, Moscow Reg., Russia.
| | - V Kuncser
- National Institute of Materials Physics, Bucharest-Magurele, 077125, Romania
| | - Rodica Turcu
- National Institute for Research and Development of Isotopic and Molecular Technologies (INCDTIM), Donat Str. 67-103, 400293 Cluj-Napoca, Romania
| | - Etelka Tombácz
- University of Szeged, Faculty of Engineering, Department of Food Engineering, Moszkvai krt. 5-7, H-6725 Szeged, Hungary.
- University of Pannonia - Soós Ernő Water Technology Research and Development Center, H-8800 Zrínyi M. str. 18, Nagykanizsa, Hungary
| | - L Vékás
- Romanian Academy - Timisoara Branch, Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Mihai Viteazu Ave. 24, 300223 Timisoara, Romania.
- Politehnica University of Timisoara, Research Center for Complex Fluids Systems Engineering, Mihai Viteazul Ave. 1, 300222 Timisoara, Romania
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5
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e Castro LL, Amorim CCC, Miranda JPV, Cassiano TDSA, Paula FLDO. The role of small separation interactions in ferrofluid structure. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2021.128082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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Mohapatra DK, Camp PJ, Philip J. Influence of size polydispersity on magnetic field tunable structures in magnetic nanofluids containing superparamagnetic nanoparticles. NANOSCALE ADVANCES 2021; 3:3573-3592. [PMID: 36133709 PMCID: PMC9419785 DOI: 10.1039/d1na00131k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/23/2021] [Indexed: 06/01/2023]
Abstract
We probe the influence of particle size polydispersity on field-induced structures and structural transitions in magnetic fluids (ferrofluids) using phase contrast optical microscopy, light scattering and Brownian dynamics simulations. Three different ferrofluids containing superparamagnetic nanoparticles of different polydispersity indices (PDIs) are used. In a ferrofluid with a high PDI (∼0.79), thin chains, thick chains, and sheets are formed on increasing the in-plane magnetic field, whereas isotropic bubbles, and hexagonal and lamellar/stripe structures are formed on increasing the out-of-plane magnetic field over the same range. In contrast, no field-induced aggregates are seen in the sample with low polydispersity under the above conditions. In a polydisperse sample, bubbles are formed at a very low magnetic field strength of 30 G. Insights into the structural evolution with increasing magnetic field strength are obtained by carrying out Brownian dynamics simulations. The crossovers from isotropic, through hexagonal columnar, to lamellar/stripe structures observed with increasing field strength in the high-polydispersity sample indicate the prominent roles of large, more strongly interacting particles in structural transitions in ferrofluids. Based on the observed microstructures, a phase diagram is constructed. Our work opens up new opportunities to develop optical devices and access diverse structures by tuning size polydispersity.
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Affiliation(s)
- Dillip Kumar Mohapatra
- Smart Materials Section, Corrosion Science and Technology Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, HBNI Kalpakkam-603102 India
| | - Philip J Camp
- School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ Scotland UK
- Department of Theoretical and Mathematical Physics, Institute of Natural Sciences and Mathematics, Ural Federal University 51 Lenin Avenue Ekaterinburg 620000 Russia
| | - John Philip
- Smart Materials Section, Corrosion Science and Technology Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, HBNI Kalpakkam-603102 India
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7
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Fu Y, Zhao G, Zhao H, Wan Z, Jia W. Investigation into a Conductive Composite Matrix Based on Magnetically Sensitive Flexible Sponges. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c02239] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Yu Fu
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, China
- Key Laboratory of Ministry of Education of Grain Information Processing and Control, Henan University of Technology, Zhengzhou 450001, China
| | - Gang Zhao
- College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China
| | - Honghao Zhao
- Department of Decision Sciences, School of Business, Macau University of Science and Technology, Macau 999078, China
| | - Zhenshuai Wan
- School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Weikun Jia
- College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China
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8
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Fu Y, Yao J, Zhao H, Zhao G, Qiu Y. Simulation of a bidisperse magnetorheological fluid using the combination of a two-component lattice Boltzmann method and a discrete element approach. SOFT MATTER 2019; 15:6867-6877. [PMID: 31411231 DOI: 10.1039/c9sm01408j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, a two-component lattice Boltzmann method (TLBM) in combination with a discrete element approach (DEA) based on a representative volume element (RVE) with respect to a bidisperse magnetorheological fluid (MRF) was performed to simulate the behavior and microstructure formation of magnetic particles in a carrier liquid. The bidisperse MRF reported herein is a suspension dispersed by soft micron carbonyl iron (CI) particles and Fe3O4 nanoparticles dual-coated with gelatin and multi-walled carbon nanotubes (MWCNTs) in the carrier liquid. In the TLBM of two-component liquid and particle simulation, the inter-particle interactions were completely ignored; on the other hand, the DEA was just employed for calculating the dynamic behavior of particles. Therefore, due to the explicit nature of the combination of TLBM and DEA, it is a more efficient and accurate strategy for the simulation and calculation of complex MRF systems. Moreover, the immersed boundary method (IBM) was used to describe the interactions between the magnetic particles and the carrier liquid. The RVE of the bidisperse MRF was selected to eliminate specific operational conditions and reduce the calculation costs. New numerical results were obtained for the motion velocities, microstructure evolution and kinetic energy of bidisperse magnetic particles (BMPs) under the effect of a magnetic field; when the mass fraction of the nanoparticles was 0.1, the bidisperse MRF exhibited an improved response time in terms of the particle motion and microstructure formation. In addition, the effects of the Reynolds (Re) and Hartmann (Ha) numbers on the fluid-particle interaction and flow velocity were illustrated.
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Affiliation(s)
- Yu Fu
- College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China
| | - Jianjun Yao
- College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China
| | - Honghao Zhao
- Department of Decision Sciences, School of Business, Macau University of Science and Technology, Macau 999078, China.
| | - Gang Zhao
- College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China
| | - Ying Qiu
- College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China
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9
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Vega-Bellido GI, DeLaCruz-Araujo RA, Kretzschmar I, Córdova-Figueroa UM. Self-assembly of magnetic colloids with shifted dipoles. SOFT MATTER 2019; 15:4078-4086. [PMID: 30942785 DOI: 10.1039/c8sm02591f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The self-assembly of colloidal magnetic Janus particles with a laterally displaced (or shifted), permanent dipole in a quasi-two-dimensional system is studied using Brownian dynamics simulations. The rate of formation of clusters and their structures are quantified for several values of dipolar shift from the particle center, which is nondimensionalized using the particle's radius so that it takes values ranging from 0 to 1, and examined under different magnetic interaction strengths relative to Brownian motion. For dipolar shifts close to 0, chain-like structures are formed, which grow at long times following a power law, while particles of shift higher than 0.2 generally aggregate in ring-like clusters that experience limited growth. In the case of shifts between 0.4 and 0.5, the particles tend to aggregate in clusters of 3 to 6, while for all shifts higher than 0.6 clusters rarely contain more than 3 particles due to the antiparallel dipole orientations that are most stable at those shifts. The strength of the magnetic interactions hastens the rate at which clusters are formed; however, the effect it has on cluster size is lessened by increases in the shift of the dipoles. These results contribute to better understand the dynamics of magnetic Janus particles and can help the synthesis of functionalized materials for specific applications such as drug delivery.
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Affiliation(s)
- Gabriel I Vega-Bellido
- Department of Chemical Engineering, University of Puerto Rico - Mayagüez, Mayagüez, PR 00681, USA.
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10
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Robinson DR, Wilson M. Field-induced self-assembly: does size matter? Mol Phys 2018. [DOI: 10.1080/00268976.2018.1481233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- David R. Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Mark Wilson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
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11
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Bidisperse Magnetic Particles Coated with Gelatin and Graphite Oxide: Magnetorheology, Dispersion Stability, and the Nanoparticle-Enhancing Effect. NANOMATERIALS 2018; 8:nano8090714. [PMID: 30208649 PMCID: PMC6163660 DOI: 10.3390/nano8090714] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/08/2018] [Accepted: 09/10/2018] [Indexed: 11/16/2022]
Abstract
The magnetorheology and dispersion stability of bidisperse magnetic particles (BMP)-based magnetorheological (MR) fluids were improved by applying a novel functional coating composed of gelatin and graphite oxide (GO) to the surfaces of the micron-sized carbonyl iron (CI) and nanoparticles Fe3O4. Gelatin acted as a grafting agent to reduce the aggregation and sedimentation of CI particles and prevent nanoparticles Fe3O4 from oxidation. In addition, a dense GO network on the surface of gelatin-coated BMP was synthesized by self-assembly to possess a better MR performance and redispersibility. The rheological properties of MR fluids containing dual-coated BMP were measured by a rotational rheometer under the presence of magnetic field and their dispersion stability was examined through sedimentation tests. The results showed that CI@Fe3O4@Gelatin@GO (CI@Fe3O4@G@GO) particles possessed enhanced MR properties and dispersion stability. In addition, the nanoparticle-enhancing effects on the dispersion stability of BMP-based MR fluids were investigated using Monte Carlo simulations.
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12
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Taheri M, Mohammadpourfard M, Sadaghiani A, Kosar A. Wettability alterations and magnetic field effects on the nucleation of magnetic nanofluids: A molecular dynamics simulation. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.03.075] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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13
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Minina ES, Pyanzina ES, Novak EV, Kantorovich SS. Compressibility of ferrofluids: Towards a better understanding of structural properties. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:67. [PMID: 29845486 DOI: 10.1140/epje/i2018-11678-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/14/2018] [Indexed: 06/08/2023]
Abstract
This paper addresses a computational method aimed at obtaining the isothermal compressibility of ferrofluids by means of molecular dynamics (MD) simulations. We model ferrofluids as a system of dipolar soft spheres and carry out MD simulations in the NPT ensemble. The obtained isothermal compressibility computed via volume fluctuations provides us with a strong evidence that dipolar interactions lead to a higher compressibility of dipolar soft sphere systems: the stronger the dipolar interactions, the bigger is the deviation of the compressibility from the one of a system with no dipoles. Furthermore, we use the isothermal compressibility to calculate the structure factor of ferrofluids at low values of wave vectors, i.e. in the range where it is difficult to predict its behaviour because of a problem with accounting for long-range particle correlations that give the main contribution to the structure factor in this range. Our approach based on the interpolation of the structure factor and the computed isothermal compressibility allows us to obtain the smooth structure factor in the range of low wave vectors and the reliable fractal dimension of the clusters formed in the system.
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Affiliation(s)
- Elena S Minina
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, Vienna, Austria.
- Ural Federal University, Lenin av. 51, Ekaterinburg, Russia.
| | | | | | - Sofia S Kantorovich
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, Vienna, Austria
- Ural Federal University, Lenin av. 51, Ekaterinburg, Russia
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14
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Minina ES, Blaak R, Kantorovich SS. Pressure and compressibility factor of bidisperse magnetic fluids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:145101. [PMID: 29465409 DOI: 10.1088/1361-648x/aab137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work, we investigate the pressure and compressibility factors of bidisperse magnetic fluids with relatively weak dipolar interactions and different granulometric compositions. In order to study these properties, we employ the method of diagram expansion, taking into account two possible scenarios: (1) dipolar particles repel each other as hard spheres; (2) the polymer shell on the surface of the particles is modelled through a soft-sphere approximation. The theoretical predictions of the pressure and compressibility factors of bidisperse ferrofluids at different granulometric compositions are supported by data obtained by means of molecular dynamics computer simulations, which we also carried out for these systems. Both theory and simulations reveal that the pressure and compressibility factors decrease with growing dipolar correlations in the system, namely with an increasing fraction of large particles. We also demonstrate that even if dipolar interactions are too weak for any self-assembly to take place, the interparticle correlations lead to a qualitative change in the behaviour of the compressibility factors when compared to that of non-dipolar spheres, making the dependence monotonic.
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Affiliation(s)
- Elena S Minina
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria. Ural Federal University, Lenin av. 51, 620000 Ekaterinburg, Russia
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15
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Weeber R, Hermes M, Schmidt AM, Holm C. Polymer architecture of magnetic gels: a review. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:063002. [PMID: 29261097 DOI: 10.1088/1361-648x/aaa344] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this review article, we provide an introduction to ferrogels, i.e. polymeric gels with embedded magnetic particles. Due to the interplay between magnetic and elastic properties of these materials, they are promising candidates for engineering and biomedical applications such as actuation and controlled drug release. Particular emphasis will be put on the polymer architecture of magnetic gels since it controls the degrees of freedom of the magnetic particles in the gel, and it is important for the particle-polymer coupling determining the mechanisms available for the gel deformation in magnetic fields. We report on the different polymer architectures that have been realized so far, and provide an overview of synthesis strategies and experimental techniques for the characterization of these materials. We further focus on theoretical and simulational studies carried out on magnetic gels, and highlight their contributions towards understanding the influence of the gels' polymer architecture.
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Affiliation(s)
- Rudolf Weeber
- Institut für Computerphysik, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
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16
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Ronti M, Rovigatti L, Tavares JM, Ivanov AO, Kantorovich SS, Sciortino F. Free energy calculations for rings and chains formed by dipolar hard spheres. SOFT MATTER 2017; 13:7870-7878. [PMID: 29019510 DOI: 10.1039/c7sm01692a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We employ a method based on Monte Carlo grand-canonical simulations to precisely calculate partition functions of non-interacting chains and rings formed by dipolar hard spheres (DHS) at low temperature. The extended low temperature region offered by such cluster calculations, compared to what had been previously achieved with standard simulations, opens up the possibility of exploring a part of the DHS phase diagram which was inaccessible before. The reported results offer the unique opportunity of verifying well-established theoretical models based on the ideal gas of cluster approximation in order to clarify their range of validity. They also provide the basis for future studies in which cluster-cluster interactions will be included.
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Affiliation(s)
- Michela Ronti
- University of Vienna, Sensengasse 8, 1090 Vienna, Austria.
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17
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Gustafson KS, Xu G, Freed KF, Qin J. Image method for electrostatic energy of polarizable dipolar spheres. J Chem Phys 2017; 147:064908. [DOI: 10.1063/1.4997620] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kyle S. Gustafson
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
| | - Guoxi Xu
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
| | - Karl F. Freed
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, USA
| | - Jian Qin
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
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18
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Cacciola M, Osaci M. Studies about the influence of self-organization of colloidal magnetic nanoparticles on the magnetic Néel relaxation time. COLLOID JOURNAL 2016. [DOI: 10.1134/s1061933x16040037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Li W, Jie O, Liu Q. Numerical simulations of the structure of ferromagnetic fluids based on dissipative particle dynamics method. MOLECULAR SIMULATION 2016. [DOI: 10.1080/08927022.2015.1102251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Wuming Li
- Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an, China
| | - Ouyang Jie
- Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an, China
| | - Qingsheng Liu
- Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an, China
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20
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Hajalilou A, Mazlan SA, Abbasi M, Lavvafi H. Fabrication of spherical CoFe2O4 nanoparticles via sol–gel and hydrothermal methods and investigation of their magnetorheological characteristics. RSC Adv 2016. [DOI: 10.1039/c6ra13493a] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
CoFe2O4 nanoparticles are synthesized through sol–gel and facile hydrothermal methods, and their magnetorheological (MR) characteristics are evaluated.
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Affiliation(s)
- Abdollah Hajalilou
- VSE Research Laboratory
- Malaysia–Japan International Institute of Technology (MJIIT)
- Universiti Teknologi Malaysia (UTM)
- Malaysia
| | - Saiful Amri Mazlan
- VSE Research Laboratory
- Malaysia–Japan International Institute of Technology (MJIIT)
- Universiti Teknologi Malaysia (UTM)
- Malaysia
| | - Mehrdad Abbasi
- Materials Science and Engineering Department
- Islamic Azad University
- Iran
| | - Hossein Lavvafi
- University of Toledo Medical Center
- Department of Radiation Oncology
- Dana Cancer Center
- Toledo
- USA
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Novak EV, Pyanzina ES, Kantorovich SS. Behaviour of magnetic Janus-like colloids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:234102. [PMID: 26010700 DOI: 10.1088/0953-8984/27/23/234102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a theoretical study of Janus-like magnetic particles at low temperature. To describe the basic features of the Janus-type magnetic colloids, we put forward a simple model of a spherical particle with a dipole moment shifted outwards from the centre and oriented perpendicular to the particle radius. Using direct calculations and molecular dynamics computer simulations, we investigate the ground states of small clusters and the behaviour of bigger systems at low temperature. In both cases the important parameter is the dipolar shift, which leads to different ground states and, as a consequence, to a different microscopic behaviour in the situation when the thermal fluctuations are finite. We show that the head-to-tail orientation of dipoles provides a two-particle energy minima only if the dipoles are not shifted from the particle centres. This is one of the key differences from the system of shifted dipolar particles (sd-particles), in which the dipole was shifted outwards radially, studied earlier (Kantorovich et al 2011 Soft Matter 7 5217-27). For sd-particles the dipole could be shifted out of the centre for almost 40% before the head-to-tail orientation was losing its energetic advantage. This peculiarity manifests itself in the topology of the small clusters in the ground state and in the response of the Janus-like particle systems to an external magnetic field at finite temperatures.
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23
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Starr FW, Sciortino F. "Crystal-clear" liquid-liquid transition in a tetrahedral fluid. SOFT MATTER 2014; 10:9413-9422. [PMID: 25349962 DOI: 10.1039/c4sm01835d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
For a model known to exhibit liquid-liquid transitions, we examine how varying the bond orientational flexibility affects the stability of the liquid-liquid transition relative to that of the crystal phases. For very rigidly oriented bonds, the crystal is favored over all amorphous phase transitions. We find that increasing the bond flexibility decreases both the critical temperature Tc for liquid-liquid phase separation and the melting temperature Tm. The effect of increasing flexibility is much stronger for melting, so that the distance between Tc and Tm progressively reduces and inverts sign. Under these conditions, a "naked" liquid-liquid critical point bulges out in the liquid phase and becomes accessible, without the possibility of crystallization. These results confirm that a crystal-clear, liquid-liquid transition can occur as a genuine, thermodynamically stable phenomenon for tetrahedral coordinated particles with flexible bond orientation, but that such a transition is hidden by crystallization when bonds are highly directional.
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Affiliation(s)
- Francis W Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA.
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24
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Camp PJ, Elfimova EA, Ivanov AO. The effects of polydispersity on the initial susceptibilities of ferrofluids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:456002. [PMID: 25327692 DOI: 10.1088/0953-8984/26/45/456002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The effects of particle-size polydispersity on the initial susceptibilities of concentrated ferrofluids are analyzed using a combination of theory and computer simulation. The study is focused on a model ferrofluid with a prescribed magnetic-core diameter distribution, a fixed non-magnetic surface layer (corresponding to a demagnetized layer and adsorbed surfactant) and a combination of dipolar and hard-core interactions. The non-trivial effects of polydispersity are identified by comparing the initial susceptibilities of monodisperse and polydisperse ferrofluids with the same Langevin susceptibility. The theory is based on a correction to the second-order modified mean-field theory arising from a formal Mayer-type cluster expansion; this correction is dependent on a parameter similar to the normal dipolar coupling constant, except that it contains a complicated double average over the particle-size distribution, which means that the initial susceptibility should depend significantly on polydispersity. Specifically, the theory predicts that the initial susceptibility is enhanced significantly by polydispersity. This prediction is tested rigorously against results from Monte Carlo simulations and is found to be robust. The qualitative agreement between theory and simulation is already satisfactory, but the quantitative agreement could be improved by a systematic extension of the cluster expansion. The overall conclusion is that polydispersity should be accounted for carefully in magnetogranulometric analyses of real ferrofluids.
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Affiliation(s)
- Philip J Camp
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, UK
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25
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Joseph A, Mathew S. Ferrofluids: Synthetic Strategies, Stabilization, Physicochemical Features, Characterization, and Applications. Chempluschem 2014. [DOI: 10.1002/cplu.201402202] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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26
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Novak E, Minina E, Pyanzina E, Kantorovich S, Ivanov A. Structure factor of model bidisperse ferrofluids with relatively weak interparticle interactions. J Chem Phys 2014; 139:224905. [PMID: 24329091 DOI: 10.1063/1.4834635] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In the present manuscript we develop a theoretical approach to describe the pair correlation function of bidisperse magnetic dipolar hard- and soft-spheres. We choose bidisperse system as the first step to allow for polydispersity when studying thermodynamics of magnetic fluids. Using diagram technique we calculate the virial expansion of the pair correlation function up to the first order in density and fourth order in the dipolar strength. Even though, the radial distribution functions are extremely sensitive to the steric potential, we show that the behaviour of the isotropic centre-centre structure factor is almost indifferent to the type of the short-range repulsion. We extensively compare our theoretical results to the data of molecular dynamics simulations, which helps us to understand the range of validity of the virial expansion both on density and magnetic dipolar strength. We also investigate the influence of the granulometric composition on the height, width, and position of the structure factor first peak in order to clarify whether it is possible to extract structural information from experimentally measured small angle neutron scattering intensities.
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Affiliation(s)
- Ekaterina Novak
- Institute of Mathematics, Department of Mathematical Physics, Ural Federal University, Lenin av. 51, 620000 Ekaterinburg, Russia
| | - Elena Minina
- Institute for Computational Physics, Universiät Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Elena Pyanzina
- Institute of Mathematics, Department of Mathematical Physics, Ural Federal University, Lenin av. 51, 620000 Ekaterinburg, Russia
| | - Sofia Kantorovich
- Institute of Mathematics, Department of Mathematical Physics, Ural Federal University, Lenin av. 51, 620000 Ekaterinburg, Russia
| | - Alexey Ivanov
- Institute of Mathematics, Department of Mathematical Physics, Ural Federal University, Lenin av. 51, 620000 Ekaterinburg, Russia
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27
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Dugay J, Tan RP, Loubat A, Lacroix LM, Carrey J, Fazzini PF, Blon T, Mayoral A, Chaudret B, Respaud M. Tuning deposition of magnetic metallic nanoparticles from periodic pattern to thin film entrainment by dip coating method. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9028-9035. [PMID: 25000178 DOI: 10.1021/la404044e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this work, we report on the self-assembly of bimetallic CoFe carbide magnetic nanoparticles (MNPs) stabilized by a mixture of long chain surfactants. A dedicated setup, coupling dip coating and sputtering chamber, enables control of the self-assembly of MNPs from regular stripe to continuous thin films under inert atmosphere. The effects of experimental parameters, MNP concentration, withdrawal speed, amount, and nature of surfactants, as well as the surface state of the substrates are discussed. Magnetic measurements revealed that the assembled particles were not oxidized, confirming the high potentiality of our approach for the controlled deposition of highly sensitive MNPs.
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Affiliation(s)
- J Dugay
- Laboratoire de Physique et Chimie des Nano-Objets, Université de Toulouse; INSA, UPS , 135, av. de Rangueil, F-31077 Toulouse, France and
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28
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Józefczak A, Hornowski T, Závišová V, Skumiel A, Kubovčíková M, Timko M. Acoustic wave in a suspension of magnetic nanoparticle with sodium oleate coating. JOURNAL OF NANOPARTICLE RESEARCH : AN INTERDISCIPLINARY FORUM FOR NANOSCALE SCIENCE AND TECHNOLOGY 2014; 16:2271. [PMID: 24672282 PMCID: PMC3955142 DOI: 10.1007/s11051-014-2271-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/10/2014] [Indexed: 06/03/2023]
Abstract
The ultrasonic propagation in the water-based magnetic fluid with doubled layered surfactant shell was studied. The measurements were carried out both in the presence as well as in the absence of the external magnetic field. The thickness of the surfactant shell was evaluated by comparing the mean size of magnetic grain extracted from magnetization curve with the mean hydrodynamic diameter obtained from differential centrifugal sedimentation method. The thickness of surfactant shell was used to estimate volume fraction of the particle aggregates consisted of magnetite grain and surfactant layer. From the ultrasonic velocity measurements in the absence of the applied magnetic field, the adiabatic compressibility of the particle aggregates was determined. In the external magnetic field, the magnetic fluid studied in this article becomes acoustically anisotropic, i.e., velocity and attenuation of the ultrasonic wave depend on the angle between the wave vector and the direction of the magnetic field. The results of the ultrasonic measurements in the external magnetic field were compared with the hydrodynamic theory of Ovchinnikov and Sokolov (velocity) and with the internal chain dynamics model of Shliomis, Mond and Morozov (attenuation).
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Affiliation(s)
- A. Józefczak
- Institute of Acoustics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - T. Hornowski
- Institute of Acoustics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - V. Závišová
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia
| | - A. Skumiel
- Institute of Acoustics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - M. Kubovčíková
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia
| | - M. Timko
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia
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29
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Avdeev MV. Particle interaction in polydisperse magnetic fluids: Experimental aspects of small-angle neutron scattering applications. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2013.05.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Weeber R, Klinkigt M, Kantorovich S, Holm C. Microstructure and magnetic properties of magnetic fluids consisting of shifted dipole particles under the influence of an external magnetic field. J Chem Phys 2013; 139:214901. [DOI: 10.1063/1.4832239] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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Sreekumari A, Ilg P. Slow relaxation in structure-forming ferrofluids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:042315. [PMID: 24229180 DOI: 10.1103/physreve.88.042315] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Indexed: 06/02/2023]
Abstract
We study the behavior of colloidal magnetic fluids at low density for various dipolar interaction strengths by performing extensive Langevin dynamics simulations with model parameters that mimic cobalt-based ferrofluids used in experiments. Our study mainly focuses on the structural and dynamical properties of dipolar fluids and the influence of structural changes on their dynamics. Drastic changes from chainlike to networklike structures in the absence of an external magnetic field are observed. This crossover plays an important role in the slowing down of dynamics that is reflected in various dynamical properties including the tracer diffusion and the viscosity and also in the structural relaxation.
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Affiliation(s)
- Aparna Sreekumari
- Polymer Physics, Department of Materials, ETH Zürich, Wolfgang-Pauli Strasse 10, CH-8093 Zürich, Switzerland
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32
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Bakuzis AF, Branquinho LC, Luiz e Castro L, de Amaral e Eloi MT, Miotto R. Chain formation and aging process in biocompatible polydisperse ferrofluids: experimental investigation and Monte Carlo simulations. Adv Colloid Interface Sci 2013; 191-192:1-21. [PMID: 23360743 DOI: 10.1016/j.cis.2012.12.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 12/27/2012] [Accepted: 12/28/2012] [Indexed: 11/25/2022]
Abstract
We review the use of Monte Carlo simulations in the description of magnetic nanoparticles dispersed in a liquid carrier. Our main focus is the use of theory and simulation as tools for the description of the properties of ferrofluids. In particular, we report on the influence of polydispersity and short-range interaction on the self-organization of nanoparticles. Such contributions are shown to be extremely important for systems characterized by particles with diameters smaller than 10nm. A new 3D polydisperse Monte Carlo implementation for biocompatible magnetic colloids is proposed. As an example, theoretical and simulation results for an ionic-surfacted ferrofluid dispersed in a NaCl solution are directly compared to experimental data (transmission electron microscopy - TEM, magneto-transmissivity, and electron magnetic resonance - EMR). Our combined theoretical and experimental results suggest that during the aging process two possible mechanisms are likely to be observed: the nanoparticle's grafting decreases due to aggregate formation and the Hamaker constant increases due to oxidation. In addition, we also briefly discuss theoretical agglomerate formation models and compare them to experimental data.
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33
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Smallenburg F, Vutukuri HR, Imhof A, van Blaaderen A, Dijkstra M. Self-assembly of colloidal particles into strings in a homogeneous external electric or magnetic field. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:464113. [PMID: 23114053 DOI: 10.1088/0953-8984/24/46/464113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Colloidal particles with a dielectric constant (magnetic susceptibility) mismatch with the surrounding solvent acquire a dipole moment in a homogeneous external electric (magnetic) field. The resulting dipolar interactions can lead to aggregation of the particles into string-like clusters. Recently, several methods have been developed to make these structures permanent. However, especially when multiple particle sizes and/or more complex shapes than single spheres are used, the parameter space for these experiments is enormous. We therefore use Monte Carlo simulations to investigate the structure of the self-assembled string-like aggregates in binary mixtures of dipolar hard and charged spheres, as well as dipolar hard asymmetric dumbbells. Binary mixtures of spheres aggregate in different types of clusters depending on the size ratio of the spheres. For highly asymmetric systems, the small spheres form ring-like and flame-like clusters around strings of large spheres, while for size ratios closer to 1, alternating strings of both large and small spheres are observed. For asymmetric dumbbells, we investigate both the effect of size ratio and dipole moment ratio, leading to a large variety of cluster shapes, including chiral clusters.
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Affiliation(s)
- Frank Smallenburg
- Soft Condensed Matter, Debye Institute for NanoMaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.
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34
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Tretiakov KV, Wojciechowski KW. Elasticity of two-dimensional crystals of polydisperse hard disks near close packing: Surprising behavior of the Poisson's ratio. J Chem Phys 2012; 136:204506. [DOI: 10.1063/1.4722100] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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35
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Li J, Qiu X, Lin Y, Liu X, Fu J, Miao H, Zhang Q, Zhang T. Oscillatory-like relaxation behavior of light transmitted through ferrofluids. APPLIED OPTICS 2011; 50:5780-5787. [PMID: 22015404 DOI: 10.1364/ao.50.005780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An oscillatory-like relaxation process in which there are two valleys in the T-t curve is observed when light is transmitted through binary ferrofluids composed of both ferrimagnetic CoFe(2)O(4) nanoparticles and paramagnetic p-MgFe(2)O(4) nanoparticles in the presence of a high magnetic field and through pure (single) CoFe(2)O(4) ferrofluids in a low magnetic field. This relaxation behavior is explained using a model of a bidispersed system based on both chained and unchained particles. In such a bidispersed system, the variation of the transmitted light results mainly from the motion of the chains, with the polarized unchained particles' gas producing the modulation effect. The oscillatory-like relaxation phenomenon depends on the features of both the chained and unchained particle systems. If either the particle volume fraction of chained particles or of unchained particles is very low, or the degree of polarization of the unchained particles gas is very weak, a simple nonlinear relaxation process, giving only a valley in the T-t curve, will appear for the transmitted light. For pure CoFe(2)O(4) ferrofluids, the number of chained and unchained particles does not remain constant under different values of the magnetic field. According to the analysis of the relaxation behavior of transmitted light, it is known that binary ferrofluids based on strong magnetic CoFe(2)O(4) particles and weak magnetic p-MgFe(2)O(4) particles can be much closer to the theoretical bidispersed system than single ferrofluids containing only strong magnetic particles.
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Affiliation(s)
- Jian Li
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
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36
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Luo L, Klapp SHL, Chen X. String formation and demixing in monolayers of dipolar colloidal mixtures. J Chem Phys 2011; 135:134701. [DOI: 10.1063/1.3643324] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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37
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Probst R, Lin J, Komaee A, Nacev A, Cummins Z, Shapiro B. Planar Steering of a Single Ferrofluid Drop by Optimal Minimum Power Dynamic Feedback Control of Four Electromagnets at a Distance. JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 2011; 323:885-896. [PMID: 21218157 PMCID: PMC3014617 DOI: 10.1016/j.jmmm.2010.08.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Any single permanent or electro magnet will always attract a magnetic fluid. For this reason it is difficult to precisely position and manipulate ferrofluid at a distance from magnets. We develop and experimentally demonstrate optimal (minimum electrical power) 2-dimensional manipulation of a single droplet of ferrofluid by feedback control of 4 external electromagnets. The control algorithm we have developed takes into account, and is explicitly designed for, the nonlinear (fast decay in space, quadratic in magnet strength) nature of how the magnets actuate the ferrofluid, and it also corrects for electro-magnet charging time delays. With this control, we show that dynamic actuation of electro-magnets held outside a domain can be used to position a droplet of ferrofluid to any desired location and steer it along any desired path within that domain - an example of precision control of a ferrofluid by magnets acting at a distance.
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38
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Pyanzina E, Kantorovich S, Cerdà JJ, Ivanov A, Holm C. How to analyse the structure factor in ferrofluids with strong magnetic interactions: a combined analytic and simulation approach. Mol Phys 2010. [DOI: 10.1080/00268970902893149] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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39
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Goyal A, Hall CK, Velev OD. Self-assembly in binary mixtures of dipolar colloids: Molecular dynamics simulations. J Chem Phys 2010; 133:064511. [DOI: 10.1063/1.3477985] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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40
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Cerdà JJ, Elfimova E, Ballenegger V, Krutikova E, Ivanov A, Holm C. Behavior of bulky ferrofluids in the diluted low-coupling regime: theory and simulation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:011501. [PMID: 20365375 DOI: 10.1103/physreve.81.011501] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 12/08/2009] [Indexed: 05/29/2023]
Abstract
A theoretical formalism to predict the structure factors observed in dipolar soft-sphere fluids based on a virial expansion of the radial distribution function is presented. The theory is able to account for cases with and without externally applied magnetic fields. A thorough comparison of the theoretical results to molecular-dynamics simulations shows a good agreement between theory and numerical simulations when the fraction of particles involved in clustering is low; i.e., the dipolar coupling parameter is lambda less, similar 2, and the volume fraction is phi less, similar 0.25. When magnetic fields are applied to the system, special attention is paid to the study of the anisotropy of the structure factor. The theory reasonably accounts for the structure factors when the Langevin parameter is smaller than 5.
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Affiliation(s)
- Juan J Cerdà
- Institute for Computational Physics, Universität Stuttgart, 70569 Stuttgart, Germany
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41
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Holm C, Ivanov A, Kantorovich S, Pyanzina E. Polydispersity Influence upon Magnetic Properties of Aggregated Ferrofluids. Z PHYS CHEM 2009. [DOI: 10.1524/zpch.2006.220.1.105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Summary
In the present paper we compare the static magnetic properties of a bidisperse ferrofluid obtained via computer simulations with the predictions of the theoretical chain model. At weak fields, the computer simulations showed a strong dependence of the magnetization on the concentration of large particles. When the latter is small the magnetization behavior is close to the one given by the modified mean field approach, but at higher concentrations of large particles the initial susceptibility increases significantly. This increase cannot be described in terms of the modified mean field model for the homogeneous system. A new theoretical approach for the description of the static magnetic properties of a bidisperse ferrofluid was developed. The theoretical predictions are in good agreement with the results of a recent computer simulation study.
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42
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Prokopieva TA, Danilov VA, Kantorovich SS, Holm C. Ground state structures in ferrofluid monolayers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:031404. [PMID: 19905113 DOI: 10.1103/physreve.80.031404] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Indexed: 05/28/2023]
Abstract
A combination of analytical calculations and Monte Carlo simulations is used to find the ground state structures in monodisperse ferrofluid monolayers. Taking into account the magnetic dipole-dipole interaction between all particles in the system we observe different topological structures that are likely to exist at low temperatures. The most energetically favored structures we find are rings, embedded rings, and rings side by side, and we are able to derive analytical expressions for the total energy of these structures. A detailed analysis of embedded rings and rings side by side shows that the interring interactions are negligible. We furthermore find that a single ideal ring is the ground state structure for a ferrofluid monolayer. We compared our theoretical predictions to the results of simulated annealing data and found them to be in excellent agreement.
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43
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Patel R, Chudasama B. Hydrodynamics of chains in ferrofluid-based magnetorheological fluids under rotating magnetic field. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:012401. [PMID: 19658750 DOI: 10.1103/physreve.80.012401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Indexed: 05/28/2023]
Abstract
Ferrofluid-based magnetorheological (MR) fluid is prepared by dispersing micron-size magnetic spheres in a ferrofluid. We report here the mechanism of chain formation in ferrofluid based MR fluid, which is quite different from conventional MR fluid. Some of the nanomagnetic particles of ferrofluid filled inside the microcavities are formed due to association of large particles, and some of them are attached at the end of large particles. Under rotating magnetic field, fragmentation of a single chain into three parts is observed. Two of them are chains of micron-size magnetic particles which are suspended in a ferrofluid, and the third one is the chain of nanomagnetic particles of ferrofluid, which may be the connecting bridge between the two chains of larger magnetic particles. The rupture of a single chain provides evidence for the presence of nanomagnetic particles within the magnetic field-induced chainlike structure in this bidispersed MR fluid.
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Affiliation(s)
- Rajesh Patel
- Department of Physics, Bhavnagar University, Bhavnagar 364 022, India.
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44
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Viota JL, Durán JDG, Delgado AV. Study of the magnetorheology of aqueous suspensions of extremely bimodal magnetite particles. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2009; 29:87-94. [PMID: 19430949 DOI: 10.1140/epje/i2009-10453-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 02/05/2009] [Accepted: 03/13/2009] [Indexed: 05/27/2023]
Abstract
In this paper we describe the magnetorheological behavior of aqueous suspensions consisting of magnetite particles of two size populations, in the micrometer and nanometer scale, respectively. Previous works on the magnetorheology of oil-based fluids demonstrated that the addition of nanoparticles has a very significant effect on the intensity of the magnetorheological effect. The present contribution confirms such results in the case of aqueous fluids, based on the dependence of the yield stress and the viscosity of the bimodal suspensions on both the composition of the mixtures and the magnetic field strength. It is demonstrated that for a given concentration of micrometer particles, increasing the amount of nanometer magnetite provokes a clear enhancement in the yield stress for all the magnetic fields applied. This is proposed to be due to the formation of heterogeneous aggregates that improve the stability of the suspensions and ease the building of well-arranged field-induced structures. The behavior of both the yield stress and the post-yield viscosity agrees better with the predictions of standard chain models when the relative proportion of both types of particles confers optimum stability to the bimodal dispersions.
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Affiliation(s)
- J L Viota
- Department of Physics, University of Jaén, 23071, Jaén, Spain
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Iskakova LY, Smelchakova GA, Zubarev AY. Condensation phase transitions in ferrofluids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:011401. [PMID: 19257029 DOI: 10.1103/physreve.79.011401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Indexed: 05/27/2023]
Abstract
Experiments show that under suitable conditions magnetic particles in ferrofluids and other polar suspensions undergo condensation phase transitions and form dense liquidlike or solidlike phases. The problem of fundamental features and scenarios of the phase transitions is one of the central problems of the physics of these systems. This work deals with the theoretical study of scenarios of condensation phase transitions in ferrofluids, consisting of identical magnetic particles. Our results show that, unlike the classical condensation phase transitions, the appearance of the linear chains precedes the magnetic particle bulk condensation. The effect of the chains on the diagrams of the equilibrium phase transitions is studied.
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Affiliation(s)
- L Yu Iskakova
- Department of Mathematical Physics, Ural State University, Lenin Av., 51, 620083 Ekaterinburg, Russia
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Kim E, Stratford K, Camp PJ, Cates ME. Hydrodynamic Interactions in Colloidal Ferrofluids: A Lattice Boltzmann Study. J Phys Chem B 2008; 113:3681-93. [DOI: 10.1021/jp806678m] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eunhye Kim
- SUPA, School of Physics, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., Edinburgh Parallel Computing Centre, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., and School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Kevin Stratford
- SUPA, School of Physics, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., Edinburgh Parallel Computing Centre, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., and School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Philip J. Camp
- SUPA, School of Physics, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., Edinburgh Parallel Computing Centre, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., and School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Michael E. Cates
- SUPA, School of Physics, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., Edinburgh Parallel Computing Centre, The University of Edinburgh, JCMB, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, U.K., and School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
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Kantorovich S, Cerdà JJ, Holm C. Microstructure analysis of monodisperse ferrofluid monolayers: theory and simulation. Phys Chem Chem Phys 2008; 10:1883-95. [DOI: 10.1039/b719460a] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zubarev AY, Iskakova LY. Internal structures in two-dimensional ferrofluids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:061405. [PMID: 18233848 DOI: 10.1103/physreve.76.061405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Revised: 05/21/2007] [Indexed: 05/25/2023]
Abstract
We present the results of a theoretical study of internal microstructures in two-dimensional ferrofluids without an external magnetic field. Recent experiments with these systems demonstrate the appearance of linear chains and ringlike and various branched clusters. We consider linear chains, rings, and branched Y-like "forks." In the model of an ideal gas of noninteracting clusters, taking into account interactions only between nearest particles, we estimate the equilibrium distribution functions of the chains, forks, and rings over a number of particles in them. Our results show that for experimentally realistic situations the majority of particles are united into chains and forks, the number of particles in the rings being relatively small. The results of calculations are in qualitative agreement with experiments.
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Affiliation(s)
- A Yu Zubarev
- Department of Mathematical Physics, Ural State University, Lenin Avenue 51, Ekaterinburg, Russia
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49
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Ivanov AO, Kantorovich SS, Reznikov EN, Holm C, Pshenichnikov AF, Lebedev AV, Chremos A, Camp PJ. Magnetic properties of polydisperse ferrofluids: a critical comparison between experiment, theory, and computer simulation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:061405. [PMID: 17677261 DOI: 10.1103/physreve.75.061405] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Indexed: 05/16/2023]
Abstract
Experimental magnetization curves for a polydisperse ferrofluid at various concentrations are examined using analytical theories and computer simulations with the aim of establishing a robust method for obtaining the magnetic-core diameter distribution function p(x). Theoretical expressions are fitted to the experimental data to yield the parameters of p(x). It is shown that the majority of available theories yield results that depend strongly on the ferrofluid concentration, even though the magnetic composition should be fixed. The sole exception is the second-order modified mean-field (MMF2) theory of Ivanov and Kuznetsova [Phys. Rev. E 64, 041405 (2001)] which yields consistent results over the full experimental range of ferrofluid concentration. To check for consistency, extensive molecular dynamics and Monte Carlo simulations are performed on systems with discretized versions of p(x) corresponding as closely as possible to that of the real ferrofluid. Essentially perfect agreement between experiment, theory, and computer simulation is demonstrated. In addition, the MMF2 theory provides excellent predictions for the initial susceptibility measured in simulations.
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Affiliation(s)
- Alexey O Ivanov
- Department of Mathematical Physics, Urals State University, 51 Lenin Avenue, Ekaterinburg 620083, Russia
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Saldivar-Guerrero R, Richter R, Rehberg I, Aksel N, Heymann L, Rodriguez-Fernández OS. Viscoelasticity of mono- and polydisperse inverse ferrofluids. J Chem Phys 2006; 125:084907. [PMID: 16965057 DOI: 10.1063/1.2337576] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report on measurements of a magnetorheological model fluid created by dispersing nonmagnetic microparticles of polystyrene in a commercial ferrofluid. The linear viscoelastic properties as a function of magnetic field strength, particle size, and particle size distribution are studied by oscillatory measurements. We compare the results with a magnetostatic theory proposed by De Gans et al. [Phys. Rev. E 60, 4518 (1999)] for the case of gap spanning chains of particles. We observe these chain structures via a long distance microscope. For monodisperse particles we find good agreement of the measured storage modulus with theory, even for an extended range, where the linear magnetization law is no longer strictly valid. Moreover we compare for the first time results for mono- and polydisperse particles. For the latter, we observe an enhanced storage modulus in the linear regime of the magnetization.
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