A research team from the Institute for Polymer Research at the GKSS Research Centre Geesthacht (Teltow / Germany; www.gkss.de) in cooperation with the German Plastics Institute (DKI, Darmstadt, Germany; www.dki-online.de) has succeeded in developing plastics with shapes that can be controlled with the aid of magnetic fields. These so-called "shape-memory" plastics return to their original shape after deformation. Up to now, this memorising ability was triggered by temperature changes and light.

With this innovative technology, scientists for the first time have been able to trigger the shape change without contact. The principle is based on incorporation of finely dispersed magnetic nanoparticles of iron oxide into a polyether urethane. The particles convert the energy from a magnetic field into heat. The temperature can be adjusted to the desired level by varying the proportion of nanoparticles and the strength of the magnetic field.

The research team foresees potential applications in medical technology especially, where remote-controlled catheters could be developed. These could rinse, fill or empty organs or vessels and avoid the need for operations in some cases, says Andreas Lendlein, head of the Teltow institute.