Scientists from Lawrence Livermore National Laboratory (LLNL) design and 3D print a new kind of metamaterial that stiffens upon contact with a magnetic field. Possible applications range from soft robotics, and optic housing to smart armor, advanced suspension systems and aerospace components.
To better explain their creation scientists came up with the term Field Responsive Metamaterial. All metamaterials are characterized by some kind of emergent property that arises from the way they are put together, rather than from what elements they are constructed. Electron Quantum Metamaterials for example are renown for their ability to conduct a lot more electricity when atoms are arranged in hexagonal formation. However, what all metamaterials share in common is that once they are built for a singular purpose, they cannot be changed. At least until now.
Field Responsive Metamaterials on the other hand transform in response to external environmental conditions. A feature enabled in this case by a solid polymer structure filled with veins of magnhetorheological fluid – a kind of liquid substrate that stiffens upon contact with a magnetic field. The fluid is also ferromagnetic – i.e. all of the atoms are aligned in the same direction to increase magnetism.
The new material could be used to create artificial musculature for soft robotics – One could have have a generator apply a magnetic field to contract a synthetic bicep for example. Or smart armor and astronaut suits that become impenetrable under certain atmospheric conditions. Furthermore, this same principle could also apply to suspension systems and aerospace components.
As far as 3D printing is concerned, scientists chose Large Area Projection Microstereolithography (LAPµSL) for it’s ability to engrave a lot of microscopic detail over a large surface area. This was required for inscribing the complex magnetorheological circulatory system that enables contraction of a solid polymer structure.
“Modulating remotely applied magnetic fields results in rapid, reversible, and sizable changes of the effective stiffness of our metamaterial motifs.