Magnetorheological elastomer

Magnetorheological elastomers (MREs) (also called magnetosensitive elastomers) are a class of solids that consist of polymeric matrix with embedded micro- or nano-sized ferromagnetic particles such as carbonyl iron. As a result of this composite microstructure, the mechanical properties of these materials can be controlled by the application of magnetic field.^[1]

Fabrication

MREs are typically prepared by curing process for polymers. The polymeric material (e.g. silicone rubber) in its liquid state is mixed with iron powder and several other additives to enhance their mechanical properties.^[2] The entire mixture is then cured at high temperature. Curing in the presence of a magnetic field causes the iron particles to arrange in chain like structures resulting in an anisotropic material. If magnetic field is not applied, then iron-particles are randomly distributed in the solid resulting in an isotropic material. Recently, in 2017, an advanced technology, 3D printing has also been used to configure the magnetic particles inside the polymer matrix. ^[3]

Classification

MREs can be classified according to several parameters like: particles type, matrix, structure and distribution of particles:^{[citation needed]}

Particles magnetic properties

Soft magnetic particles
Hard magnetic particles
Magnetostrictive particles
Magnetic shape-memory particles

Matrix structure

Solid matrix
Porous matrix

Matrix electrical properties

Isolating matrix
Conductive matrix

Distribution of particles

Isotropic
Anisotropic

Theoretical Studies

In order to understand magneto-mechanical behaviour of MREs, theoretical studies need to be performed which couple the theories of electromagnetism with mechanics. Such theories are called theories of magneto-mechanics.^[4]^[5]

Programmable magnetopolymers

Magnetopolymers with large remanence are typically formed by combining hard-magnetic particles with a polymer matrix. The orientation of the magnetic particles is typically controlled with an external magnetic field during the polymerization process, and then mechanically fixed after the material is synthesized. Because the Curie temperature of these magnetopolymers exceeds the temperature at which the polymer matrix would break down, they must be degaussed in order to be remagnetized. This means that the functionality of these magnetopolymers is limited and they can only be permanently programmed during manufacturing.

Programmable magnetopolymers embed athermal ferromagnetic particles in droplets of low melting point materials in polymer matrices.^[6]^[7]^[8] Above the droplet melting point, the particles have rotational freedom. The uniqueness of these composites exists in their easily reprogrammable magnetization profiles. This behaviour follows from the fact that particles (1) are athermal, (2) have Curie temperatures above the droplet melting point, and (3) are fixated in solid droplets while possessing full rotational freedom in molten droplets. This easy reprogramming is a critical characteristic for such materials to be used in a wide range of applications.^[7]

Applications

MREs have been used for vibration isolation applications since their stiffness changes within a magnetic field ^[9]^[10]

References

^ Magnetorheology, Editor: Norman M Wereley, Royal Society of Chemistry, Cambridge 2014, https://pubs.rsc.org/en/content/ebook/978-1-84973-754-8
^ Jolly, M. R., Carlson, J. D. & Muñoz, B. C. A model of the behaviour of magnetorheological materials. Smart Mater. Struct. 5, 607–614 (1996).
^ A.K. Bastola, V.T Hoang, L. Lin. A novel hybrid magnetorheological elastomer developed by 3D printing. Materials and Design 114, 391–397 (2017) [link].
^ Kankanala, S. V. & Triantafyllidis, N. On finitely strained magnetorheological elastomers. J. Mech. Phys. Solids 52, 2869–2908 (2004).
^ Dorfmann, A. & Ogden, R. W. Magnetoelastic modelling of elastomers. Eur. J. Mech. - A/Solids 22, 497–507 (2003).
^ Song, Hyeonseo; Lee, Hajun; Lee, Jaebyeong; Choe, Jun Kyu; Lee, Suwoo; Yi, Jee Yoon; Park, Sunghoon; Yoo, Jung-Woo; Kwon, Min Sang; Kim, Jiyun (3 June 2020). "Reprogrammable Ferromagnetic Domains for Reconfigurable Soft Magnetic Actuators". Nano Letters. 20 (7): 5185–5192. Bibcode:2020NanoL..20.5185S. doi:10.1021/acs.nanolett.0c01418. eISSN 1530-6992. ISSN 1530-6984. PMID 32491865. S2CID 219319700.
^ ^a ^b Kaya, Kerem; Iseri, Emre; van der Wijngaart, Wouter (6 December 2022). "Soft metamaterial with programmable ferromagnetism". Microsystems & Nanoengineering. 8 (1): 127. Bibcode:2022MicNa...8..127K. doi:10.1038/s41378-022-00463-2. eISSN 2055-7434. PMC 9722694. PMID 36483621. This article incorporates text from this source, which is available under the CC BY 4.0 license.
^ Deng, Heng; Sattari, Kianoosh; Xie, Yunchao; Liao, Ping; Yan, Zheng; Lin, Jian (10 December 2020). "Laser reprogramming magnetic anisotropy in soft composites for reconfigurable 3D shaping". Nature Communications. 11 (1): 6325. Bibcode:2020NatCo..11.6325D. doi:10.1038/s41467-020-20229-6. eISSN 2041-1723. PMC 7730436. PMID 33303761.
^ Deng, H. X., Gong, X. L. & Wang, L. H. Development of an adaptive tuned vibration absorber with magnetorheological elastomer. Smart Mater. Struct. 15, N111-N116 (2006) [link].
^ Behrooz, M., Wang, X. & Gordaninejad, F. Performance of a new magnetorheological elastomer isolation system. Smart Mater. Struct. 23, 045014 (2014) [link].