Img/2012/5/23/unii.jpgLondon: Researchers have come up with an avant-garde material that expands every time it is put under pressure.
Under any circumstances, this metamaterial, designed by Zachary Nicolaou and Adilson Motter of Northwestern University in Evanston, Illinois, can stretch when compressed, and vice versa.
"What is interesting is that they study systems that are not responding to a vibration but to a steady applied force," the New Scientist quoted John Pendry of Imperial College London as saying.
However such sort of a thing should be impossible, because a material, which behaves in this way, is bound to be essentially unstable.
Moreover it will instantly collapse into a stable state without exhibiting such a behaviour.
Nicolaou and Motter overcame this obstacle by designing a material with an inherent structure which did not rebound back to its stable state.
It rather got transformed to a state which is more compact or expanded than the original state.
In theory, their design comprises of a row of four "particles". Each of this is made of groups of molecules, attracting each other to varying/different degrees.
The force that attracts the two particles on the inner side is weak, resulting into the breaking of bond when the material is pulled.
"As soon as that happens, the outer particles attract each other more," said Motter.
Christopher Smith at the University of Exeter, UK said that the Miniaturized versions which applies similar principles could one day be used as coatings for military vehicles, that protects them.
"If a blast hit the side of your vehicle, it would push back and try to cancel out some of the effect," he said.
Motter revealed that many of the previous work on metamaterials has pivoted itself on creating unique electromagnetic properties, which might, as well, bend light to create invisibility cloaks.
This new study is part of a up-and-coming branch of research into "mechanical" metamaterials with atypical responsiveness towards strains and stresses.
"We`ve gone almost as far as we can with high-strength materials.
"The next phase has to be materials that do completely different things,” Smith added.