Synthesis and characterization of uniaxial ferrogels with Ni nanorods as magnetic phase

Bender, Philipp; Günther, Annegret; Tschöpe, Andreas; Birringer, R.

doi:10.1016/j.jmmm.2011.03.016

Cited by 58 publications

(62 citation statements)

References 28 publications

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“…For the uniaxial case, the remanence follows cos y zy , 38,45 and decreases to 0 for y zy = 901. For both cases, one would ideally expect a maximum M r /M s = 1 for fully oriented and immobilized particles at y zy = 01.…”

Section: Motivation and Conceptmentioning

confidence: 99%

“…33 However, while particles recently used for the extraction of magnetomechanical characteristics in soft matrices are predominantly uniaxial and thus allow to model their properties on the base of an extended Stoner-Wohlfarth model, 9,38 the hematite spindles do not necessarily follow this behavior. The synthetic procedures are readily available and allow a wide range of gel compositions.…”

Section: Motivation and Conceptmentioning

confidence: 99%

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Magnetic and geometric anisotropy in particle-crosslinked ferrohydrogels

Roeder

Bender

Kundt

et al. 2015

Phys. Chem. Chem. Phys.

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Particle-crosslinked polymer composites and gels have recently been shown to possess novel or improved properties due to a covalent particle-matrix interaction. We employ spindle-like hematite particles as exclusive crosslinkers in poly(acrylamide) gels, and exploit their extraordinary magnetic properties for the realization of ferrohydrogels with a perpendicular orientation of the preferred magnetic and geometric axes of the particles. The angle-dependent magnetic properties of uniaxially oriented gels are investigated and interpreted with respect to particle-matrix interactions. The impact of the particle orientation on the resulting angle-dependent magnetic performance reveals the presence of two different contributions to the magnetization: a hysteretic component ascribed to immobilized particles, and a pseudo-superparamagnetic, non-hysteretic component due to residual particle mobility. Furthermore, a plastic reorientation of magnetic particles in the matrix when subjected to a transversal field component is observed.

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Section: Motivation and Conceptmentioning

confidence: 99%

Section: Motivation and Conceptmentioning

confidence: 99%

Magnetic and geometric anisotropy in particle-crosslinked ferrohydrogels

Roeder

Bender

Kundt

et al. 2015

Phys. Chem. Chem. Phys.

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“…Finally, Fig. (c) shows the nanowires separated from the template by chemical etching with a 4 mol l −1 NaOH solution for at least 1 h . The resulting nanowires do not have a homogeneous diameter, but the pieces of the nanowires obtained are free of cracks.…”

Section: Resultsmentioning

confidence: 99%

“…Following Refs. , it is possible to remove the alumina template by means of etching the AAO material off using a NaOH solution. We found that this works well [see Fig.…”

Section: Resultsmentioning

confidence: 99%

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Commercial alumina templates as base to fabricate 123-type high-T _c superconductor nanowires

Koblischka

Zeng

Hartmann

2015

Phys. Status Solidi A

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Nanowires of high-T c superconductors of the RE-123 type (RE ¼ rare earths) were grown by the anodized alumina template method, employing commercially available alumina templates with nominal pore diameters of 20 and 100 nm. Pre-reacted YBa 2 Cu 3 O x (YBCO) and NdBa 2 Cu 3 O x (NdBCO) powder was molten on top of the templates in order to fill the pores with the 123-type material. The resulting samples were oxygen-annealed at 450 8C. Superconductivity with a transition temperature of 88 K (YBCO) and 96 K (NdBCO) was confirmed by means of magnetic susceptibility measurements (SQUID) using pieces of the filled template. The electric (resistance) and magnetic measurements revealed further relatively sharp superconducting transitions. To understand the dimensions of the resulting nanowires (length up to 10 mm, diameter between 100 and 250 nm), which do not correspond to the nominal pore diameters, the empty and filled commercial templates were analyzed in detail by scanning electron microscopy. We discuss the feasibility of this approach to produce larger amounts of nanowires.

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Hydrogel‐Based Artificial Muscles: Overview and Recent Progress

Park

Kim

2020

Advanced Intelligent Systems

120

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Artificial muscles are promising as an intelligent material that can replace conventional power systems to reproduce the motion of a living organism. Among various building materials, hydrogels have great advantages as artificial muscles, such as responsiveness to a wide range of stimuli, large volume deformation, and sensitivity. However, conventional hydrogel actuators that generate only isotropic volume change in response to an external stimulus cannot be considered as artificial muscles because complex deformations are not possible. Instead, programmed complex deformations originated from a rationally designed anisotropic structure are desired in artificial muscles. Herein, recent approaches for constructing stimuli‐responsive hydrogels with an anisotropic structure, thereby enabling a directional complex motion to mimic a muscle are reviewed. First, stimuli‐responsive shape‐deforming hydrogels as a main building matrix are categorized according to stimulating external signals. The representative methods for modulating the isotropic structure of a hydrogel into various anisotropic structures, such as multilayer structure, linearly oriented structure, and patterned structure are discussed. Finally, the recent strategies to achieve muscle‐like motion of hydrogels by combining stimuli responsiveness and anisotropic structures for translation from elementary contraction and expansion to programmed deformations, such as multidirectional bending, directionally amplified deformation, and compositive programmed motion, are covered.

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Synthesis and characterization of uniaxial ferrogels with Ni nanorods as magnetic phase

Cited by 58 publications

References 28 publications

Magnetic and geometric anisotropy in particle-crosslinked ferrohydrogels

Magnetic and geometric anisotropy in particle-crosslinked ferrohydrogels

Commercial alumina templates as base to fabricate 123-type high-T _c superconductor nanowires

Hydrogel‐Based Artificial Muscles: Overview and Recent Progress

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Synthesis and characterization of uniaxial ferrogels with Ni nanorods as magnetic phase

Cited by 58 publications

References 28 publications

Magnetic and geometric anisotropy in particle-crosslinked ferrohydrogels

Magnetic and geometric anisotropy in particle-crosslinked ferrohydrogels

Commercial alumina templates as base to fabricate 123-type high-T c superconductor nanowires

Hydrogel‐Based Artificial Muscles: Overview and Recent Progress

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Product

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Commercial alumina templates as base to fabricate 123-type high-T _c superconductor nanowires