The new rubber-like material can absorb and release large amounts of energy by using a phase shift. (Image Credit: University of Massachusetts Amherst)
Researchers from the University of Massachusetts Amherst unveiled a new, programmable rubber-like solid substance capable of absorbing and releasing large amounts of energy. This material has promising applications, where robots can store more power without relying on extra energy, and protective gear releases energy quicker than before. This could also be used for high-force impacts or lightning-quick responses.
"Imagine a rubber band," says Alfred Crosby, professor of polymer science and engineering at UMass Amherst and the paper's senior author. "You pull it back, and when you let it go, it flies across the room. Now imagine a super rubber band. When you stretch it past a certain point, you activate extra energy stored in the material. When you let this rubber band go, it flies for a mile."
The rubber band is composed of a new metamaterial, which features an elastic, rubber-like substance with tiny magnets placed inside. It leverages a phase shift physical property to boost the energy quantity the material releases or absorbs. Phase shifts occur as material changes from one state to another. For example, you can see liquid cement hardening to form a sidewalk or water turning into steam. Energy gets released or absorbed while a material undergoes this phase shift process. This can also be used as a power source, but collecting sufficient energy has proven challenging.
"To amplify energy release or absorption, you have to engineer a new structure at the molecular or even atomic level," says Crosby. However, achieving this in a predictable approach is difficult, but with metamaterials, Crosby said, "we have overcome these challenges, and have not only made new materials but also developed the design algorithms that allow these materials to be programmed with specific responses, making them predictable."
The inspiration for this development came from Venus flytraps snapping shut and other trap-jaw plants. "We've taken this to the next level," says Xudong Liang, the paper's lead author, currently a professor at Harbin Institute of Technology, Shenzhen (HITSZ) in China who completed this research while a postdoc at UMass Amherst. "By embedding tiny magnets into the elastic material, we can control the phase transitions of this metamaterial. And because the phase shift is predictable and repeatable, we can engineer the metamaterial to do exactly what we want it to do: either absorbing the energy from a large impact or releasing great quantities of energy for explosive movement."
Energy storage from clean sources still remains an issue. Perhaps this will end up changing all that. Time will tell.
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