Though in a fluid state, magnetic particles are able to pack themselves together and act like a solid object.
In theory, liquid magnets go against all the rules. In order to create a magnetic field, particles such as iron and nickel have to be densely packed together with their orientations all facing the same direction. This is the case with solid objects, but not the same with liquid ones.
Once a magnetic liquid is no longer activated by a field, the free-floating particles that make it up start to move around and become disorganised. Because of this, the most effective magnet one would find and use would be one in a solid state. This doesn’t, however, have to be the case anymore.
A group of researchers at the Beijing University of Chemical Technology have successfully created a liquid containing particles that, when activated, can produce a magnetic field and act like tiny bars of magnets.
To create this magnetic liquid, the researchers took droplets, roughly a millimetre in size each, of a solution containing iron oxide nanoparticles and submerged them into oil mixed with a special kind of polymer. The polymer attracts nanoparticles to the surface of each droplet and pins them together, creating a magnetic field. The magnetic direction of each droplet was found to be stable (as the nanoparticles could not shift out of their positions while clustered together).
As well as this, the magnetic field was found to be strong enough to hold the other, non-magnetic particles within the droplet together. Xubo Liu, who co-authored the research study, says that the whole droplet acts like a solid magnet. He also says that while the researchers created simple shapes out of the droplets like spheres and cylinders, 3D-printing technology could be used to create more complex shapes and objects.
The question now is what can be done with liquid magnets. The technology could help mobile robots and machines and how they move around. The liquid could replace air pouches or even electrical current as a means of propulsion, then controlled by a human operator using an activated magnetic field. It could also be used to create magnetic sponges, which could wring themselves out and prevent people from having to touch dangerous chemicals.
Source: Science News