Rubber remembers

Researchers at the University of Rochester have developed a shape-memory rubber that may enable designers to make products as diverse as biomedical implants, conformal face-masks, self-sealing sutures, and "smart" labels.

Shape-memory polymers are materials that, once stretched into a new shape, stay in that form until heated, at which time they revert to their initial shape.

But unlike conventional shape-memory polymers, the new material is transparent, rubbery, and most importantly, engineers will be able to control the speed at which it returns to its original shape.

'At higher temperatures, the material stretches like a rubber band, but, at lower temperatures, it stiffens up,' said Mitchell Anthamatten, assistant Prof of chemical engineering and developer of the material.

'This property can be used to temporarily hold the material in a deformed shape, and its original shape can then be recalled by heating, ' he added.

The new material opens up the possibilities that designers could build an optical lens that can be triggered to change shape, a face-mask that can fit any user, or a biomedical implant that changes shape slow enough for a surgical procedure.