24 November 2006 – A German-US research team has developed “triple-shape plastics” which can change shape twice by means of temperature control.
The team from the GKSS Research Centre of Biomaterial Development in Teltow near Berlin and the Massachusetts Institutes of Technology in Cambridge, US, say the materials are able to perform two shape changes which do not have to be unidirectional.
It believes there is huge potential for applications in a wide variety of areas. Professor Andreas Lendlein, head of the GKSS Research Centre, said it could be used for an intelligent stent that could be inserted into a blood vessel through a small opening and then inflated at an implantation site to a full size medical device.
He also suggested a useful industrial application of the triple shape plastics. “One could think of an application in assembly technology where the anchor units of a fixing device are deployed in a first step and are locked into a precise position in a second production step,” he said.
In the new material, two types of polymer chain segments are cross-linked at the molecular level. The differences in the molecular flexibility of the two types of chain segments at different temperatures enable the change of shape.
Each of the chain segments is stable at unchanged ambient conditions, and raising the temperature induces the shape change.
