Piezoresistivity of magnetorheological elastomers

Kchit, Nadir; Bossis, Georges

doi:10.1088/0953-8984/20/20/204136

Cited by 43 publications

(55 citation statements)

References 12 publications

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“…Actually, a high degree of anisotropy was obtained by using fillers that are both highly magnetic and electrical conductors, and loading the polymer with relatively low concentration of fillers (clearly lower than those used by other authors [10,[26][27][28]). The combination of these factors when curing the composites in the presence of a uniform magnetic field is the key for getting final products with anisotropic properties.…”

Section: Discussionmentioning

confidence: 92%

“…One type of MR materials are the composites formed by dispersing magnetic filler particles into an elastomer polymeric matrix, referred as magnetorheological elastomers (MRE) [1][2][3]. A simple procedure to obtain MRE materials is curing the filler-elastomer composite in the presence of a uniform magnetic field (H curing ) which induces agglomerations of the filler particles into chain-like structures aligned in the direction of the field [4][5][6][7][8][9][10][11]. These cured composites not only present anisotropic elastic properties but the elastic moduli can be now modified by application of magnetic fields (H).…”

Section: Introductionmentioning

confidence: 99%

“…These cured composites not only present anisotropic elastic properties but the elastic moduli can be now modified by application of magnetic fields (H). Although the dependence of the Young´s modulus with H in MRE has been investigated in several comprehensive studies [6,7,9], there are two closely-related aspects concerning MRE that have not been systematically explored yet: the dependence of other physical properties with external driving forces has been scarcely reported and the implementation of real devices based on MRE is still in its very beginnings [10,12,13].…”

Section: Introductionmentioning

confidence: 99%

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Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Mietta

Jorge

Pérez

et al. 2013

Sensors and Actuators A: Physical

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An anisotropic magnetorheological composite formed by dispersions of silver-covered magnetite microparticles (Fe3O4@Ag) in polydimethylsiloxane (PDMS) displaying electrical conduction only in one preferred direction is presented. A set-up for applying and detecting electrical conduction through the composite is described and applied to characterize the behavior of the system in on-off commutation cycles. The composite is obtained by loading the polymer with relatively low concentration of fillers (5% w/w of the total weight) and curing it in the presence of a uniform magnetic field. The fillers appear in the final composite as an array of needles, i.e. pseudo-chains of particles aligned in the direction of the magnetic field. Using Fe3O4 nanoparticles (13 nm) it is possible to obtain cured composites in a superparamagnetic state, that is, without magnetic hysteresis at room temperature. Hysteresis is not found in the elastic properties either; in particular, Mullins effects (change of physical properties after the first strain-stress cycle) were not observed. No measurable transversal electrical conduction was detected (transversal resistivity larger than 62 Mohms•cm). Thus, significant electrical conductivity is present only between contact points that are exactly facing each other at both sides of the composites in the direction parallel to the needles. The I-V curves in that direction have ohmic behavior and exhibit both piezoresistance and magnetoresistance, that is, the electrical conductivity in the direction parallel to the pseudochains increases when a pressure (i.e. compressive stress) is applied at constant magnetic field and/or when a magnetic field is applied at constant pressure. The materials do not exhibit magnetoelectric or piezoresistive hysteresis. These characteristics illustrate the high potentiality of these systems in elastic connectors where electrical conduction can be varied by external mechanical or magnetic forces. List of changes following suggestions of the reviewerWe improved the language following all the suggestions of the reviewer, listed here: Table 1 Figure 7 shows the absence of significant transversal conductivity for an elastomeric connector of 2 mm thickness. Measurements were performed using the set-up shown in Figure 1.This result was observed also for samples of 1 and 3 mm thickness, which is consistent with the no variation of the resistivities (  and   ) with the sample thickness". Page 14: another sentence was rephrased: "On the other hand, no measurable current was detected between contacts that do not coincide vertically". 1) A glossary of terms is included asPage 15: "…the desired anisotropic properties, which, in this case, are stabilized by the curing of the PDMS resin".Page 15: "The fillers and the matrix appear contactless after curing."Page 15: another sentence was rephrased: "The absence of hysteresis in the elastic, piezoresistive and magnetoresistive properties can be associated to the lack of relevant adhesion between the inorganic fillers ...

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Mietta

Jorge

Pérez

et al. 2013

Sensors and Actuators A: Physical

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“…Hence, both possibilities are kept, as already indicated by Kchit and Bossis. 1 We assume that the net passage of an electron from one particle to another neighbor can be due to both mechanisms ͑contact or tunneling͒, with a global probability p whose critical value for connectivity between extremes is referred as p c . In the present work, we focalize on the conductance changes observed as function of the strain while keeping constant the amount of particles.…”

Section: Conduction Criterions and General Relationshipsmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12] We are focusing in the present work on composites of conducting particles embedded in an insulating elastomer matrix. The matrix is compressed by the action of an externally applied uniaxial pressure keeping constant the amount of conducting particles, a process that increases the electrical conductance of the composite, which can be used for obtaining a pressure sensor.…”

Section: Introductionmentioning

confidence: 99%

A model for the dependence of the electrical conductance with the applied stress in insulating-conducting composites

Negri

Rodríguez

Bernik

et al. 2010

Journal of Applied Physics

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A model for the dependence of the electrical conductance, G, with the strain induced by external mechanical stress in conducting particles-polymer composites is presented. The model assumes that the percolation probability between neighboring particles must depart from a scale-invariant behavior but saturate at moderated-high strains, reaching percolation path's saturation, with sigmoid dependence. This dependence is obtained by proposing a dynamic picture where contacts or bonds between neighboring particles are created but also destructed when a stress is applied and relatively moderated or high strains, , are produced in the composite. The electrical conductance of prepared graphite-polydimethylsiloxane composites were measured as function of the applied pressure and fitted by the presented model. The elastic response to the uniaxial compression was studied using a texture analyzer. The possibility of nonuniversal effects in the conduction critical exponent, t, was taken into account. It is concluded that the saturation of the response in the G versus plots cannot be assigned to nonuniversal behavior of the exponent t, or to saturation of the elastic response. On the other hand, the presented model accounts for all the main experimental features observed in these systems and for previously reported data of elastomer composites. The simulated behavior of the piezoresistivity coefficient is also in qualitative agreement with previous reports.

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Recent Progress on Magnetorheological Solids: Materials, Fabrication, Testing, and Applications

et al. 2014

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Magnetorheological (MR) materials are classified as smart materials due to their responsiveness to external magnetic stimuli. Intensive research on MR materials has led to broad applications in several potential fields. A solid carrier matrix state called MR elastomer with its exceptional magnetic responsive feature is obtained by merging magnetizable particles within an elastomeric polymer. This integration results in outstanding characteristics on the rheological performances. Special prominence is given to the understanding of the base materials and fabrication as well as the functional behavior through various characterization methods. Broad applications of MREs are also explored to provide a profound market picture and to motivate researchers to develop novel technology.

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Piezoresistivity of magnetorheological elastomers

Cited by 43 publications

References 12 publications

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

A model for the dependence of the electrical conductance with the applied stress in insulating-conducting composites

Recent Progress on Magnetorheological Solids: Materials, Fabrication, Testing, and Applications

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