Disclosed is a magnetic dendrimer compound and a method for preparing the magnetic dendrimer compound, the molecular formula of which is shown in formula (I): Γ(CH.sub.2).sub.3N.sub.(2.sup.n+1.sub.−1)R.sup.1.sub.(2.sup.n+2.sub.−2)R.sup.2.sub.(2.sup.n+1.sub.)(I). In this formula, Γ indicates magnetic particles coated with SiO.sub.2 on a surface thereof, the magnetic particles having been modified by a silane coupling agent; (CH.sub.2).sub.3N.sub.(2.sup.n+1.sub.−1)R.sup.1.sub.(2.sup.n+2.sub.−2) is a dendritic group, and R.sup.2.sub.(2.sup.n+1.sub.) is a lipophilic group, with 0≤n≤100. Further disclosed is a lubricant comprising the magnetic dendrimer compound.

Provided are cobalt ferrite particles having a micrometer-order average particle diameter and similar particle diameters. When a cobalt ferrite precursor is treated at a high temperature and a high pressure, an oxidation reaction is caused in the presence of a complexing agent, thereby obtaining intended cobalt ferrite magnetic particles.

Provided are magnetic particles (cobalt ferrite) having a micrometer-order average particle diameter and similar particle diameters. A cobalt ferrite precursor is heated in the presence of a sulfite, thereby obtaining intended cobalt ferrite magnetic particles.

A method of performing wireless actuation by inductive heating of magnetic particles. The method provides a bladder having an inner surface and an outer surface, the inner surface forming an interior area, the bladder configured to expand or retract so as to change an area of the interior area, (ii) a plurality of magnetic particles suspended in a fluid medium and disposed within the interior area, and (iii) a sleeve disposed on the outer surface of the bladder. The method excites the plurality of magnetic particles by application of an alternating magnetic field to which the particles reaction. The method causes, by the excited magnetic particles, a phase transition to the fluid medium within the interior area which causes the bladder to expand, such that the sleeve confining the bladder generates actuation from the expansion or retraction of the bladder.

There is provided a magnetic responsiveness composite material capable of increasing viscosity by applying a magnetic field when compounded together with a liquid in a composition. The magnetic responsive composite material comprises first particles as core particles composed of a nonmagnetic inorganic material and second particles composed of a magnetic material adhering to at least a part of surfaces of the first particles. A lipophilic treatment agent is applied to at least a part of surfaces of the second particles. The second particles satisfy a relationship of having a smaller average particle diameter than that of the first particles. A lipophilic treatment agent is preferably at least one kind selected from coupling agents and surfactants.

The invention relates to a process for moving a droplet from a first location to a second location, which droplet comprises a magnetic material disposed in an aqueous medium. The invention also relates to a droplet assembly comprising a droplet, which droplet comprises a magnetic material disposed in an aqueous medium. Various uses of the droplet assembly are also described.

A method for precise control of movement of a motive phase on a lubricant-impregnated surface includes providing a lubricant-impregnated surface, introducing the motive phase onto the lubricant-impregnated surface, and exposing the droplets to an electric and/or magnetic field to induce controlled movement of the droplets on the surface. The lubricant-impregnated surface includes a matrix of solid features spaced sufficiently close to stably contain the impregnating lubricant therebetween or therewithin. The motive phase is immiscible or scarcely miscible with the impregnating lubricant.

A magnetic powder is obtained by removing a dispersion medium from a magnetic fluid that includes magnetic particles, a dispersant and the dispersion medium. A magnetic powder composition includes the magnetic powder and a resin material, and a magnetic powder composition molded body is obtained therefrom. A method of producing a magnetic powder includes removing a dispersion medium from a magnetic fluid containing magnetic particles, a dispersant and the dispersion medium, and powdering a solid component obtained by removing the dispersion medium. A method of producing a magnetic powder composition and a method of producing a magnetic powder composition molded product are also provided.

Various examples are provided related to surfaces that can achieve controllable dynamic iridescence. In one example, a magnetically actuated surface includes an array of magnetic nanopillars; and a ferrofluid sealed in a microfluidic channel over the array of magnetic nanopillars. In another example, a method for forming a magnetically actuated surface includes generating a 2D periodic array of recesses in a photoresist layer; generating a nanopillar template from the 2D periodic array of recesses in the photoresist layer; forming a microfluidic channel over the nanopillar template; and filling the microfluidic channel with a ferrofluid comprising magnetic nanoparticles in a fluid medium.

The invention relates to a process for moving a droplet from a first location to a second location, which droplet comprises a magnetic material disposed in an aqueous medium. The invention also relates to a droplet assembly comprising a droplet, which droplet comprises a magnetic material disposed in an aqueous medium. Various uses of the droplet assembly are also described.