Adv. Mater. (2014)

The practical potential of graphene fibres (GFs) stems from the fact they combine the mechanical strength and flexibility of fibres with the electronic and thermal characteristics of graphene. Recently, a spinning technique for fabricating GFs directly from graphene oxide has galvanized research in this area, as this provides a large-scale and low-cost route to fibres with a range of different functionalities that one can envisage being useful in textiles for wearable electronics. Now, Liangti Qu and colleagues from the Beijing Institute of Technology demonstrate an intriguing concept for GFs, in the form of moisture-operated twisting graphene motors. Depending on the degree of twisting they are subjected to, different twist angles can be introduced in the GFs. Once a particular twist angle has been set, it can be reversibly tuned by exposing the fibres to moisture. The authors then make use of this property to fabricate an electric generator in which the application of vapour leads to a twisted GF switching the magnetization of a small magnet, which in turn drives a small electric field in copper coils surrounding it.