Polymers

Research

13 pages, 2280 KiB

Open AccessArticle

Design of Arbitrary Magnetic Patterns on Magnetic Polymer Composite Objects: A Finite Element Modelling Tool

by Pedro González-Losada, Marco Martins, Elvira Paz, K. B. Vinayakumar, Domingos Pereira, Ana R. Cortez and Diogo Elói Aguiam

Polymers 2022, 14(18), 3713; https://doi.org/10.3390/polym14183713 - 6 Sep 2022

Cited by 1 | Viewed by 1522

Abstract

Magnetic sensor systems integrate a sensing element and magnetic field generators to determine their relative position or to measure movement. Typically, the magnetic fields are produced by permanent magnets, which have high intensity but are hard to machine into custom shapes. However, novel [...] Read more.

Magnetic sensor systems integrate a sensing element and magnetic field generators to determine their relative position or to measure movement. Typically, the magnetic fields are produced by permanent magnets, which have high intensity but are hard to machine into custom shapes. However, novel solutions using magnetic polymer composites (MPCs) have emerged as field generators due to their low cost, weight and patterning freedom. Here, we present a finite element model developed in COMSOL Multiphysics that allows the design of complex magnetization patterns on these polymer composites, taking into account the geometries of the parts and the magnetic properties of the materials employed. The model, together with the characterization protocol of the materials, has proved to be capable of predicting the magnetization of polymer composites at different temperatures. In addition, the model incorporates the properties of the magnets used during the magnetization process, such as the size, shape and magnetization, as well as the properties of the surrounding elements. This new model facilitates the design of new polymeric parts with complex shapes and magnetization patterns that can be employed as field generators in magnetic sensing systems. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Figure 1

11 pages, 1932 KiB

Open AccessArticle

Multiferroic Coupling of Ferromagnetic and Ferroelectric Particles through Elastic Polymers

by Liudmila A. Makarova, Danil A. Isaev, Alexander S. Omelyanchik, Iuliia A. Alekhina, Matvey B. Isaenko, Valeria V. Rodionova, Yuriy L. Raikher and Nikolai S. Perov

Polymers 2022, 14(1), 153; https://doi.org/10.3390/polym14010153 - 31 Dec 2021

Cited by 5 | Viewed by 2477

Abstract

Multiferroics are materials that electrically polarize when subjected to a magnetic field and magnetize under the action of an electric field. In composites, the multiferroic effect is achieved by mixing of ferromagnetic (FM) and ferroelectric (FE) particles. The FM particles are prone to [...] Read more.

Multiferroics are materials that electrically polarize when subjected to a magnetic field and magnetize under the action of an electric field. In composites, the multiferroic effect is achieved by mixing of ferromagnetic (FM) and ferroelectric (FE) particles. The FM particles are prone to magnetostriction (field-induced deformation), whereas the FE particles display piezoelectricity (electrically polarize under mechanical stress). In solid composites, where the FM and FE grains are in tight contact, the combination of these effects directly leads to multiferroic behavior. In the present work, we considered the FM/FE composites with soft polymer bases, where the particles of alternative kinds are remote from one another. In these systems, the multiferroic coupling is different and more complicated in comparison with the solid ones as it is essentially mediated by an electromagnetically neutral matrix. When either of the fields, magnetic or electric, acts on the ‘akin’ particles (FM or FE) it causes their displacement and by that perturbs the particle elastic environments. The induced mechanical stresses spread over the matrix and inevitably affect the particles of an alternative kind. Therefore, magnetization causes an electric response (due to the piezoeffect in FE) whereas electric polarization might entail a magnetic response (due to the magnetostriction effect in FM). A numerical model accounting for the multiferroic behavior of a polymer composite of the above-described type is proposed and confirmed experimentally on a polymer-based dispersion of iron and lead zirconate micron-size particles. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Graphical abstract

13 pages, 4048 KiB

Open AccessArticle

Reconfigurable Surface Micropatterns Based on the Magnetic Field-Induced Shape Memory Effect in Magnetoactive Elastomers

by Matija Lovšin, Dominik Brandl, Gašper Glavan, Inna A. Belyaeva, Luka Cmok, Lucija Čoga, Mitjan Kalin, Mikhail Shamonin and Irena Drevenšek-Olenik

Polymers 2021, 13(24), 4422; https://doi.org/10.3390/polym13244422 - 16 Dec 2021

Cited by 8 | Viewed by 2835

Abstract

A surface relief grating with a period of 30 µm is embossed onto the surface of magnetoactive elastomer (MAE) samples in the presence of a moderate magnetic field of about 180 mT. The grating, which is represented as a set of parallel stripes [...] Read more.

A surface relief grating with a period of 30 µm is embossed onto the surface of magnetoactive elastomer (MAE) samples in the presence of a moderate magnetic field of about 180 mT. The grating, which is represented as a set of parallel stripes with two different amplitude reflectivity coefficients, is detected via diffraction of a laser beam in the reflection configuration. Due to the magnetic-field-induced plasticity effect, the grating persists on the MAE surface for at least 90 h if the magnetic field remains present. When the magnetic field is removed, the diffraction efficiency vanishes in a few minutes. The described effect is much more pronounced in MAE samples with larger content of iron filler (80 wt%) than in the samples with lower content of iron filler (70 wt%). A simple theoretical model is proposed to describe the observed dependence of the diffraction efficiency on the applied magnetic field. Possible applications of MAEs as magnetically reconfigurable diffractive optical elements are discussed. It is proposed that the described experimental method can be used as a convenient tool for investigations of the dynamics of magnetically induced plasticity of MAEs on the micrometer scale. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Graphical abstract

15 pages, 6834 KiB

Open AccessArticle

Dielectric Spectroscopy of Hybrid Magnetoactive Elastomers

by Vitaliy G. Shevchenko, Gennady V. Stepanov and Elena Yu. Kramarenko

Polymers 2021, 13(12), 2002; https://doi.org/10.3390/polym13122002 - 18 Jun 2021

Cited by 8 | Viewed by 2642

Abstract

Dielectric properties of two series of magnetoactive elastomers (MAEs) based on a soft silicone matrix containing 35 vol% of magnetic particles were studied experimentally in a wide temperature range. In the first series, a hybrid filler representing a mixture of magnetically hard NdFeB [...] Read more.

Dielectric properties of two series of magnetoactive elastomers (MAEs) based on a soft silicone matrix containing 35 vol% of magnetic particles were studied experimentally in a wide temperature range. In the first series, a hybrid filler representing a mixture of magnetically hard NdFeB particles of irregular shape and an average size of 50 μm and magnetically soft carbonyl iron (CI) of 4.5 μm in diameter was used for MAE fabrication. MAEs of the second series contained only NdFeB particles. The presence of magnetically hard NdFeB filler made it possible to passively control MAE dielectric response by magnetizing the samples. It was shown that although the hopping mechanism of MAEs conductivity did not change upon magnetization, a significant component of DC conductivity appeared in the magnetized MAEs presumably due to denser clustering of interacting particles resulting in decreasing interparticle distances. The transition from a non-conducting to a conducting state was more pronounced for hybrid MAEs containing both NdFeB and Fe particles with a tenfold size mismatch. Hybrid MAEs also demonstrated a considerable increase in the real part of the complex relative permittivity upon magnetization and its asymmetric behavior in external magnetic fields of various directions. The effects of magnetic filler composition and magnetization field on the dielectric properties of MAEs are important for practical applications of MAEs as elements with a tunable dielectric response. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Figure 1

28 pages, 7232 KiB

Open AccessArticle

A Cascading Mean-Field Approach to the Calculation of Magnetization Fields in Magnetoactive Elastomers

by Dirk Romeis and Marina Saphiannikova

Polymers 2021, 13(9), 1372; https://doi.org/10.3390/polym13091372 - 22 Apr 2021

Cited by 6 | Viewed by 2888

Abstract

We consider magnetoactive elastomer samples based on the elastic matrix and magnetizable particle inclusions. The application of an external magnetic field to such composite samples causes the magnetization of particles, which start to interact with each other. This interaction is determined by the [...] Read more.

We consider magnetoactive elastomer samples based on the elastic matrix and magnetizable particle inclusions. The application of an external magnetic field to such composite samples causes the magnetization of particles, which start to interact with each other. This interaction is determined by the magnetization field, generated not only by the external magnetic field but also by the magnetic fields arising in the surroundings of interacting particles. Due to the scale invariance of magnetic interactions (

O (r^{- 3})

in

d = 3

dimensions), a comprehensive description of the local as well as of the global effects requires a knowledge about the magnetization fields within individual particles and in mesoscopic portions of the composite material. Accordingly, any precise calculation becomes technically infeasible for a specimen comprising billions of particles arranged within macroscopic sample boundaries. Here, we show a way out of this problem by presenting a greatly simplified, but accurate approximation approach for the computation of magnetization fields in the composite samples. Based on the dipole model to magnetic interactions, we introduce the cascading mean-field description of the magnetization field by separating it into three contributions on the micro-, meso-, and macroscale. It is revealed that the contributions are nested into each other, as in the Matryoshka’s toy. Such a description accompanied by an appropriate linearization scheme allows for an efficient and transparent analysis of magnetoactive elastomers under rather general conditions. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Graphical abstract

25 pages, 792 KiB

Open AccessArticle

Constitutive Model of Isotropic Magneto-Sensitive Rubber with Amplitude, Frequency, Magnetic and Temperature Dependence under a Continuum Mechanics Basis

by Bochao Wang and Leif Kari

Polymers 2021, 13(3), 472; https://doi.org/10.3390/polym13030472 - 2 Feb 2021

Cited by 11 | Viewed by 2986

Abstract

A three-dimensional nonlinear constitutive model of the amplitude, frequency, magnetic and temperature dependent mechanical property of isotropic magneto-sensitive (MS) rubber is developed. The main components of MS rubber are an elastomer matrix and magnetizable particles. When a magnetic field is applied, the modulus [...] Read more.

A three-dimensional nonlinear constitutive model of the amplitude, frequency, magnetic and temperature dependent mechanical property of isotropic magneto-sensitive (MS) rubber is developed. The main components of MS rubber are an elastomer matrix and magnetizable particles. When a magnetic field is applied, the modulus of MS rubber increases, which is known as the magnetic dependence of MS rubber. In addition to the magnetic dependence, there are frequency, amplitude and temperature dependencies of the dynamic modulus of MS rubber. A continuum mechanical framework-based constitutive model consisting of a fractional standard linear solid (SLS) element, an elastoplastic element and a magnetic stress term of MS rubber is developed to depict the mechanical behavior of MS rubber. The novelty is that the amplitude, frequency, magnetic and temperature dependent mechancial properties of MS rubber are integrated into a whole constitutive model under the continuum mechanics frame. Comparison between the simulation and measurement results shows that the fitting effect of the developed model is very good. Therefore, the constitutive model proposed enables the prediction of the mechanical properties of MS rubber under various operating conditions with a high accuracy, which will drive MS rubber’s application in engineering problems, especially in the area of MS rubber-based anti-vibration devices. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Figure 1

9 pages, 3006 KiB

Open AccessArticle

Magnetorheological Response for Magnetic Elastomers Containing Carbonyl Iron Particles Coated with Poly(methyl methacrylate)

by Daichi Takahashi, Annadanam Venkata Sesha Sainath, Junko Ikeda, Kulisara Budpud, Tatsuo Kaneko, Mika Kawai and Tetsu Mitsumata

Polymers 2021, 13(3), 335; https://doi.org/10.3390/polym13030335 - 21 Jan 2021

Cited by 6 | Viewed by 2243

Abstract

The magnetorheological response for magnetic elastomers containing carbonyl iron (CI) particles with a diameter of 6.7 μm coated with poly(methyl methacrylate) (PMMA) was investigated to estimate the diameter of secondary particles from the amplitude of magnetorheological response. Fourier-transformed infrared spectroscopy revealed that the [...] Read more.

The magnetorheological response for magnetic elastomers containing carbonyl iron (CI) particles with a diameter of 6.7 μm coated with poly(methyl methacrylate) (PMMA) was investigated to estimate the diameter of secondary particles from the amplitude of magnetorheological response. Fourier-transformed infrared spectroscopy revealed that the CI particles were coated with PMMA, and the thickness of the PMMA layer was determined to be 71 nm by density measurement. The change in the storage modulus for magnetic elastomers decreased by coating and it was scaled by the number density of CI particles as ΔG~N^2.8. The diameter of secondary particle of CI particles coated with PMMA was calculated to be 8.4 μm. SEM images revealed that the CI particles coated with PMMA aggregated in the polyurethane matrix. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Graphical abstract

13 pages, 915 KiB

Open AccessArticle

Large-Scale Shape Transformations of a Sphere Made of a Magnetoactive Elastomer

by Oleg Stolbov and Yuriy Raikher

Polymers 2020, 12(12), 2933; https://doi.org/10.3390/polym12122933 - 8 Dec 2020

Cited by 10 | Viewed by 2244

Abstract

Magnetostriction effect, i.e., deformation under the action of a uniform applied field, is analyzed to detail for a spherical sample of a magnetoactive elastomer (MAE). A close analogy with the field-induced elongation of spherical ferrofluid droplets implies that similar characteristic effects viz. hysteresis [...] Read more.

Magnetostriction effect, i.e., deformation under the action of a uniform applied field, is analyzed to detail for a spherical sample of a magnetoactive elastomer (MAE). A close analogy with the field-induced elongation of spherical ferrofluid droplets implies that similar characteristic effects viz. hysteresis stretching and transfiguration into a distinctively nonellipsoidal bodies, should be inherent to MAE objects as well. The absence until now of such studies seems to be due to very unfavorable conclusions which follow from the theoretical estimates, all of which are based on the assumption that a deformed sphere always retains the geometry of ellipsoid of revolution just changing its aspect ratio under field. Building up an adequate numerical modelling tool, we show that the ‘ellipsoidal’ approximation is misleading beginning right from the case of infinitesimal field strengths and strain increments. The results obtained show that the above-mentioned magnetodeformational effect should distinctively manifest itself in the objects made of quite ordinary MAEs, e.g., composites on the base of silicone cautchouc filled with micron-size carbonyl iron powder. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Figure 1

15 pages, 583 KiB

Open AccessArticle

Coupled Anisotropic Magneto-Mechanical Material Model for Structured Magnetoactive Materials

by Eike Dohmen and Benjamin Kraus

Polymers 2020, 12(11), 2710; https://doi.org/10.3390/polym12112710 - 16 Nov 2020

Cited by 9 | Viewed by 2369

Abstract

Adaptability of properties of magnetic materials such as magnetorheological (MR) fluids, MR elastomers (MRE), and other magneto-active (MA) materials drives scientific activities worldwide, trying to broaden the fields of application of such materials. In our work, we focused on the utilization and implementation [...] Read more.

Adaptability of properties of magnetic materials such as magnetorheological (MR) fluids, MR elastomers (MRE), and other magneto-active (MA) materials drives scientific activities worldwide, trying to broaden the fields of application of such materials. In our work, we focused on the utilization and implementation of existing material models to realize a praxis-oriented coupled anisotropic material model for the commercial finite element (FE) software ABAQUS taking into account magneto-mechanical interactions. By introducing this material model, a first step is done to predict and optimize the behavior of MA materials. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Figure 1

23 pages, 4256 KiB

Open AccessArticle

Magnetorheological Effect of Magnetoactive Elastomer with a Permalloy Filler

by Dmitry Borin, Gennady Stepanov, Anton Musikhin, Andrey Zubarev, Anton Bakhtiiarov and Pavel Storozhenko

Polymers 2020, 12(10), 2371; https://doi.org/10.3390/polym12102371 - 15 Oct 2020

Cited by 20 | Viewed by 2856 | Correction

Abstract

Within the frames of this study, the synthesis of a permalloy to be used as a filler for magnetoactive and magnetorheological elastomers (MAEs and MREs) was carried out. By means of the mechanochemical method, an alloy with the composition 75 wt.% of Fe [...] Read more.

Within the frames of this study, the synthesis of a permalloy to be used as a filler for magnetoactive and magnetorheological elastomers (MAEs and MREs) was carried out. By means of the mechanochemical method, an alloy with the composition 75 wt.% of Fe and 25 wt.% of Ni was obtained. The powder of the product was utilized in the synthesis of MAEs. Study of the magnetorheological (MR) properties of the elastomer showed that in a ~400 mT magnetic field the shear modulus of the MAE increased by a factor of ~200, exhibiting an absolute value of ~8 MPa. Furthermore, we obtained experimentally a relative high loss factor for the studied composite; this relates to the size and morphology of the synthesized powder. The composite with such properties is a very perspective material for magnetocontrollable damping devices. Under the action of an external magnetic field, chain-like structures are formed inside the elastomeric matrix, which is the main determining factor for obtaining a high MR effect. The effect of chain-like structures formation is most pronounced in the region of small strains, since structures are partially destroyed at large strains. A proposed theoretical model based on chain formation sufficiently well describes the experimentally observed MR effect. The peculiarity of the model is that chains of aggregates of particles, instead of individual particles, are considered. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Figure 1

Review

Jump to: Research, Other

42 pages, 3887 KiB

Open AccessReview

Theoretical Modeling of Magnetoactive Elastomers on Different Scales: A State-of-the-Art Review

by Timur A. Nadzharyan, Mikhail Shamonin and Elena Yu. Kramarenko

Polymers 2022, 14(19), 4096; https://doi.org/10.3390/polym14194096 - 29 Sep 2022

Cited by 20 | Viewed by 2807

Abstract

A review of the latest theoretical advances in the description of magnetomechanical effects and phenomena observed in magnetoactive elastomers (MAEs), i.e., polymer networks filled with magnetic micro- and/or nanoparticles, under the action of external magnetic fields is presented. Theoretical modeling of magnetomechanical coupling [...] Read more.

A review of the latest theoretical advances in the description of magnetomechanical effects and phenomena observed in magnetoactive elastomers (MAEs), i.e., polymer networks filled with magnetic micro- and/or nanoparticles, under the action of external magnetic fields is presented. Theoretical modeling of magnetomechanical coupling is considered on various spatial scales: from the behavior of individual magnetic particles constrained in an elastic medium to the mechanical properties of an MAE sample as a whole. It is demonstrated how theoretical models enable qualitative and quantitative interpretation of experimental results. The limitations and challenges of current approaches are discussed and some information about the most promising lines of research in this area is provided. The review is aimed at specialists involved in the study of not only the magnetomechanical properties of MAEs, but also a wide range of other physical phenomena occurring in magnetic polymer composites in external magnetic fields. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures

Figure 1

20 pages, 12881 KiB

Open AccessReview

Magnetic Polymer Composite Particles: Design and Magnetorheology

by Qi Lu, Kisuk Choi, Jae-Do Nam and Hyoung Jin Choi

Polymers 2021, 13(4), 512; https://doi.org/10.3390/polym13040512 - 8 Feb 2021

Cited by 48 | Viewed by 8048

Abstract

As a family of smart functional hybrid materials, magnetic polymer composite particles have attracted considerable attention owing to their outstanding magnetism, dispersion stability, and fine biocompatibility. This review covers their magnetorheological properties, namely, flow curve, yield stress, and viscoelastic behavior, along with their [...] Read more.

As a family of smart functional hybrid materials, magnetic polymer composite particles have attracted considerable attention owing to their outstanding magnetism, dispersion stability, and fine biocompatibility. This review covers their magnetorheological properties, namely, flow curve, yield stress, and viscoelastic behavior, along with their synthesis. Preparation methods and characteristics of different types of magnetic composite particles are presented. Apart from the research progress in magnetic polymer composite synthesis, we also discuss prospects of this promising research field. Full article

(This article belongs to the Special Issue Magnetic Polymer Composites: Design and Application)

► Show Figures