Actuation of Iron Oxide‐Based Nanostructures by External Magnetic Fields

Abstract

Iron oxide nanoparticles can be used for the actuation of nanostructures with external magnetic fields. Most commonly the iron oxides magnetite or maghemite are used. Iron oxides are advantageous for actuation, as they have a high permanent magnetic moment, are nontoxic and relatively stable. External magnetic fields can exert forces and torques on the particles, which can be used to actuate individual nanostructures or to guide the self-assembly of large numbers of magnetic nanostructures. The external magnetic fields can thus act as a fuel for nanomachines or can provide the energy needed to drive a system of interacting nanostructures out of thermal equilibrium. Many interesting discoveries have been made along these lines in recent years, some of which are reviewed in this chapter

Chained Iron Microparticles for Directionally Controlled Actuation of Soft Robots

“…Soft polymer composites containing embedded magnetic particles, where applied magnetic fields modulate the mechanical properties of the composite, are known as magnetorheological elastomers (MREs), and magnetoactive elastomers (MAEs) are a subset of MREs that undergo shape changes in applied magnetic fields . In MAEs, magnetic actuation may be caused either by torques, when a homogeneous magnetic field acts to align magnetic moments, or by forces generated by magnetic field gradients. − While these are fundamentally distinct effects, they may occur simultaneously in some magnetic field geometries. Furthermore, assembling the particles into chains within the polymer enhances the magnetic response and imparts directional actuation, since alignment of the chains in the direction of the magnetic field is energetically favored .…”

Control and manipulation of nanoparticles for fabrication of metal matrix composites

“…Magnetic field assisted assembly in particular has attracted the interest of many researchers due to its relatively fast stimuli-response behavior [40,158]. It has showed promising capabilities for use in many applications such as actuators [159,160], optoelectronic devices [148], optical diffraction gratings [161] and photonic crystal [162], biomedical applications [163,164], composites [165][166][167], solar cells [168], electronics, and sensors [169].…”