A new synthetic material has been shown to have interchangeable stiffness when it comes in contact with magnets. This metamaterial—an artificial structure comprised of a grid-like network of plastic tubes filled with fluid that becomes more viscous in a magnetic field—causes the tubes to firm up in a magnetic field, allowing the tube to turn from soft to rigid in a split second.

The Experiment

Christopher Spadaccini, a materials engineer at Lawrence Livermore National Laboratory in California, and his colleagues put this metamaterial to work by 3-D printing lattices composed of plastic struts and injecting them with a mixture of tiny iron particles and oil—the metamaterial.

When close to a magnet, the iron microparticles aligned into chains along the magnetic field lines, making the fluid viscous and the lattices stiffer. On the other hand, when the magnet was absent, the iron microparticles remained scattered randomly throughout the oil, leaving a runny liquid. They found when they shifted the unit cell -- hollow, die-shaped structures of the new material that can collectively form larger lattices -- from eight centimeters to one centimeter away from the magnet, its stiffness increased by about 62%.

Why This is Important

A solid chunk of iron microparticle filled material would not only be heavy but also very expensive to make. Building tubular structures that are mostly open space makes the material lightweight and less expensive.

In future technology, this material can be paired with devices that use electricity to generate magnetic fields, called electromagnets. The material could also aid in making more adaptable robots. Robots with interchangeable stiffness would be able to squeeze into small spaces, but could also be sturdy enough to carry or move other objects.

It would also serve a functional purpose for body armor, such as sports pads. Material that becomes softer or stiffer on demand can be used to make next-generation sports pads or helmets with tunable impact absorption.

Learn More About Apex Magnets
Even though we here at Apex Magnets do not have the metamaterial (how cool would that be?) we do have a large variety of interesting and quite frankly, addicting, sizes and shapes of magnets. For more break-through magnetic discoveries, browse through our magnet in the news section.