Ever wonder why all our gadgets are rigid rectangles? It doesn’t have anything to do with the outside of the device, but the inside. Electronics are full of conductive sheets, which are basically responsible for shooting electricity and data between components. While technically flexible, conductive sheets are designed to be flat, and become less efficient when they bend due to tearing. It’s why our smartphones only gently curve, why our tablets don’t fold, and why our wearables seem underpowered.
But that might all be set to change. A University of Michgan research team lead by Professor Nicholas Kotov has figured out a way to apply Japanese paper cutting techniques, called kirigami, to a new type of flexible conductor, opening the door to gadgets that bend, flex, fold, and transform. Why not print out conductive sheets that were pre-cut to rip in artful (and very conductive) ways?
The first prototype of the kirigami stretchable conductor consisted of tracing paper covered in graphene nanotubes. The layout was very simple, with cuts like rows of dashes that opened to resemble a cheese grater. Later concepts, though, we more complicated: Terry Shyo, a doctoral student in materials science at U.Mich, made later conductor sheets out of graphene oxide, etching cuts into the surface just a tenth of a millimeter long using laser beams and a plasma of oxygen ions and electrons.
According to Kotov, the reason no one has ever pre-cut these conductive sheets before has to do with material science. “In principle, you can do this with sheets of metal,” Kotov says. “But the homogeneity of the material is a factor.” There are impurities, especially in composites, which can make the microscopic cuts go off course. Graphene, however, made an optimal medium for their electro-kirigami technique, which is why this has never been done before.
But what does it all mean for the gadgets of the future? Kotov tells me his technique opens up big possibilities for implantable medical devices, which have to flex and bend within the human body to work. But gadgets that won’t break when bending or flexing is another possibility: the day of totally transformable devices may well be at hand. Even flexible batteries could happen thanks to kirigami. The day when your Apple Watch’s battery lasts a week because it’s strung out all across the band may be closer than you think.
See more information about the study here.