Have you ever heard about foldable glass? Exactly. Glass is notorious for its brittleness. Although industry has developed ultra-thin (?0.1 mm), flexible glass (like Corning's Willow® Glass) that can be bent for applications liked curved TV and smartphone displays, fully foldable glass had not been demonstrated. Until now.
Usually, the thinner a substrate or device is, the more flexible it becomes. Folding can be considered an extreme case of bending. Researchers already made progress towards foldable electronics ("Nanotechnology research produces foldable graphene electronics on paper"), origami-foldable solar cells, and foldable Li-ion batteries.
"The use of ultrathin substrates (usually with a thickness of 1-2 microns) is especially suitable for conformable, patch-like skin sensors or devices, whereas it's not so suitable for displays or other applications due to its mechanical instability," Dahl-Young Khang, an Associate Professor in the Department of Materials Science and Engineering at Yonsei University, tells Nanowerk. "Such ultrathin substrates – and devices fabricated on it – can easily be buckled or crumpled."