Magnetically Tunable Elasticity for Magnetic Hydrogels Consisting of Carrageenan and Carbonyl Iron Particles

Abstract

A new class of magnetoelastic gel that demonstrates drastic and reversible changes in storage modulus without using strong magnetic fields was obtained. The magnetic gel consists of carrageenan and carbonyl iron particles. The magnetic gel with a volume fraction of magnetic particles of 0.30 exhibited a reversible increase by a factor of 1400 of the storage modulus upon a magnetic field of 500 mT, which is the highest value in the past for magnetorheological soft materials. It is considered that the giant magnetoelastic behavior is caused by both high dispersibility and high mobility of magnetic particles in the carrageenan gel. The off-field storage modulus of the magnetic gel at volume fractions below 0.30 obeyed the Krieger-Dougherty equation, indicating random dispersion of magnetic particles. At 500 mT, the storage modulus was higher than 4.0 MPa, which is equal to that of magnetic fluids, indicating that the magnetic particles move and form a chain structure by magnetic fields. Morphological study revealed the evidence that the magnetic particles embedded in the gel were aligned in the direction of magnetic fields, accompanied by stretching of the gel network. We conclude that the giant magnetoelastic phenomenon originates from the chain structure consisting of magnetic particles similar to magnetic fluids.

Starch-coated magnetic liposomes as an inhalable carrier for accumulation of fasudil in the pulmonary vasculature

“…Also, this approach can adversely influence biodistribution (Chouly et al, 1996), weaken drug-particle interaction and enhance drug-particle dissociation (Alexiou et al, 2000; Arias et al, 2008; Kim and Lee, 2001). Magnetic nanoparticles can also be encapsulated into various particulate carriers such as liposomes (Pradhan et al, 2010), polymeric nanoparticles (Li et al, 2011) and magnetic hydrogels (Mitsumata et al, 2012). Of the particulate carriers, liposomes are widely used microscopic spherical vesicles that can encapsulate both lipophilic and hydrophilic drug molecules in their lipid bilayer and aqueous core (Laouini, 2012).…”

Magnetoelastic Behavior of Bimodal Magnetic Hydrogels Using Nonmagnetic Particles

“…At 0 mT, the storage modulus of magnetic gels was independent of the mixing ratio. In the previous papers, 8,9 it was shown that the CI particles are randomly dispersed in carrageenan gels. Therefore, it can be considered that the dispersibility of the particles is not influenced by the particle mixing.…”

“…However, we showed evidence that iron particles move within the crosslinked gel and make a structure with the alignment of magnetic particles (chain structure). 9 A few years ago, Klingenberg et al reported interesting behavior that the yield stress of magnetorheological fluids was enhanced by the presence of nonmagnetizable particles. 10 This behavior presents us an idea that the nonmagnetic particle is able to participate in forming the chain structure.…”

Magnetically tunable viscoelastic response of soft magnetic nanocomposites with wormlike surfactant micellar matrix

“…This makes it difficult to disperse the submicron-or micron-sized particles in a liquid carrier. To resolve this problem, highly viscous carriers [11] or polymer network matrices [13,14] can be used. However, these carriers deteriorate the mechanical properties of the system in magnetic field because of the restriction of the motion of the particles within the network [14] and the delay rate of the response [13].…”

“…To resolve this problem, highly viscous carriers [11] or polymer network matrices [13,14] can be used. However, these carriers deteriorate the mechanical properties of the system in magnetic field because of the restriction of the motion of the particles within the network [14] and the delay rate of the response [13]. To compensate these negative effects, the concentration of particles should be increased considerably (up to 30 vol %) [14].…”