materiaux

The rapid development of ultra-thin electronic skins (e-skins) – also called epidermal electronics or electronic tattoos – is opening new realms of possibility for flexible and stretchable monitoring gadgets that are wearable directly on the skin. These e-skin devices can be used for, among other things, prosthetics and rehabilitation, optogenetics, human-machine interfaces, human-computer interaction in gaming, and as diagnostic tools in the medical field (read more on this topic in « Lab-on-skin: Nanotechnology electronics for wearable health monitoring »).

Alloys that can return to their original structure after being deformed have a so-called shape memory. This phenomenon and the resulting forces are used in many mechanical actuating systems, for example in generators or hydraulic pumps. However, it has not been possible to use this shape-memory effect at a small nanoscale: Objects made of shape-memory alloy can only change back to their original shape if they are larger than around 50 nanometers.