Shape-Changing Plastics Developed for Medical, Industrial Applications

JOM, Jan 2007

Rearchers at the Massachusetts Institute of Technology (MIT) and the Helmholtz Association of German Research Centers have developed materials that can assume three different shapes, depending on how much heat is applied. The agile plastics could find use in medical and industrial applications.

"Triple-shape materials can switch from shape A, then to shape B, and on to shape C," said Andreas Lendlein, a polymer chemist at the Helmholtz Institute in Teltow, Germany. "Using two, rather than just one, shape-changes offers unique opportunities for applications such as intelligent stents or smart fastener systems."

An intelligent stem made of the plastic material could assume three different shapes throughout a meidical procedure, depending on how much heat is applied: an oval shape for insertion; a fully inflated round shape tor temporary use inside a blood vessel, duct, or other cylindrical organ; and a compressed cylindrical shape for easy removal.

In factories, the material could be used to create changeable plastic fasteners. The fasteners could be implanted in, or attached to, a part and then heated to extend an arm to another part. With further heating, the fastener would change shape yet again to lock itself in place (Figure 1).

"It's like a new principle in materials, and it will be producing new opportunities," said Robert Langer, a chemical engineer at MIT. "It's the first time I've seen sumething that will go from shape A to shape B and then shape C."