materiaux

Since its first demonstration in 2004, the large-scale commercial production of graphene has proven difficult and costly (‘large scale’ usually defined as weights more than 200 mg or films larger than 200 cm2). For instance, at an estimated cost of $50 000 to $200 000 per ton for graphene powders and $45 000 to $100 000 per m2 of graphene film, industrial production methods and costs are restraining graphene utility.

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.