Phys.org  May 4, 2018
An international team of researchers (France, Switzerland, Germany) used responsive materials to generate structures with built-in complex geometries, linear actuators and microswimmers. The results suggest that complex, fully functional machines composed solely from shape-changing materials might be possible. They show that prestrained polymer fibres closed into rings exhibit self-actuation and continuous motion when placed between two heat baths due to elastic deformations that arise from rotational-symmetry breaking around the rod’s axis. Their findings illustrate a simple but robust model to create active motion in mechanically prestrained objects… read more. TECHNICAL ARTICLE
With the wheel within, the researchers hit upon an extremely simple principle to set polymer material into spontaneous motion. Credit: Falko Ziebert (263)