The potentiality of composite elastic magnets as novel materials for sensors and actuators

Lanotte, L.; Ausanio, G.; Hison, C.; Iannotti, V.; Luponio, C.

doi:10.1016/s0924-4247(03)00133-x

Cited by 37 publications

(26 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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%

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Mietta

Jorge

Pérez

et al. 2013

Sensors and Actuators A: Physical

View full text Add to dashboard Cite

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 ...

show abstract

Section: Introductionmentioning

confidence: 99%

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Mietta

Jorge

Pérez

et al. 2013

Sensors and Actuators A: Physical

View full text Add to dashboard Cite

show abstract

“…These effects into a solid matrix are totally inhibited by the mechanical reaction, but in the case of polymeric fibers that are easily deformable, a local rotation with a fiber aligning towards the tube axis is expected until the elastic reaction torque equilibrates the magnetic one [45]. Generally, any particle has a slight rotation, thus producing an elongation of the sample, namely a direct elastomagnetic effect [50]. In the case under investigation, the Ni particles form clusters into the fiber (average cluster width smaller than fiber diameter but length of about 5-6 particle diameter; see section 3.1 and Figure 5d.…”

Section: Magneto-elastic Response and Characterizationmentioning

confidence: 99%

Electrospun nanofiber tubes with elastomagnetic properties for biomedical use

Guarino¹,

Ausanio²,

Iannotti³

et al. 2018

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract.Electrospinning technique has been successfully used to produce composite nanofibers combining magnetic nanoparticles with polymer matrices. Process conditions to assembly nanofibers in tubular systems, as well as their morphological and elastomagnetic properties, have been explored. A volume percentage of magnetic charge close to 30% has been achieved. The optimization of the fabrication method ensures that the particles are completely covered by a thin polymer shell, so safe-guarding bio-compatibility. In particular, the deformation induced by the direct elastomagnetic effect, applying a static or a pulsed magnetic field, has been investigated. Resultant devices exhibit good elastomagnetic stretchability at room temperature-longitudinal relative strain/exciting field ~4·10 -3 /(1.5·10 4 A/m) -, thus suggesting their potential use for applications in biomedical field as magneto-active components, as well as sensors and actuators.

show abstract

“…In particular, the inverse elastomagnetic effect is exhibited: strain appears when its state of magnetization is changed, due to the alignment or rotation of magnetic particles and it is not depending on the intrinsic magnetostriction of the particles [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Magneto-piezoresistivity in iron particle-filled silicone: An alternative outlook for reading magnetic field intensity and direction

Iannotti¹,

Ausanio²,

Lanotte³

2016

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract. Elastomagnetic effect (strain induced by magnetic field application) and piezoresistivity (change of electron conductivity due to an induced strain) are coupled in composite materials constituted by magnetic and conductive microparticles into an elastic matrix. On the basis of these effects, the principle of a new method to read magnetization direction changes, in a random sequence, is proposed and experimentally demonstrated. We have produced new composite magnetopiezoresistive samples, constituted of thin chip shaped Fe microparticles inside a silicone matrix, which under an applied magnetic field along their longitudinal axis, undergo an induced strain depending on the local magnetization direction. The resulting resistivity change can be easily detected and used to deduce the local magnetization direction. The magnetization and strain processes are reversible so that after the removal of external magnetizing field the sample is ready for new measurements. A demonstrator prototype has been conceived, produced and tested. The experimental results provide interesting data encouraging to continue the research towards nano-scale devices in order to pursue the intriguing perspective to achieve a magnetic field gradient sensitivity able to reveal magnetization of semipermanent nanomagnets, polarized 'up' and 'down'.

show abstract

The potentiality of composite elastic magnets as novel materials for sensors and actuators

Cited by 37 publications

References 11 publications

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Electrospun nanofiber tubes with elastomagnetic properties for biomedical use

Magneto-piezoresistivity in iron particle-filled silicone: An alternative outlook for reading magnetic field intensity and direction

Contact Info

Product

Resources

About