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New Material Can Fold Itself Into Hundreds of Shapes (sciencemag.org)
sciencehabit writes: Researchers have created the first heat-reactive polymer material that can not only remember its current shape but also memorize new ones. The material—which currently requires high temperatures to change shape and reset its memory—could lead to a new generation of reusable self-folding materials that could be useful for everything from medical implants to shape-shifting electronics (abstract). The new substance has transition temperatures of 70C and 130C for elasticity and plasticity, respectively. To demonstrate its multishape capabilities, Xie's team turned a 30-millimeter square of the material into an origami masterpiece that could fold between two shapes using elasticity and change into other shapes using plasticity. Not only did the material fold into multiple different shapes, but it could also snap between them hundreds of times with little sign of fatigue—a critical feature if the material is to be used in real-world applications, they report today in Science Advances.
Shape Memory Alloy are a Nickel Titainium alloy often called muscle wire because by changing its crystal structure it gets shorter when heated or an electric current runs through it. While very different in how it works from a polymer, Shape Memory Alloy has had similar uses including heart stints, explosive bolt replacements on spacecraft, toys and heating air vent controls. Biggest down side to it is it tends to be a bit slow so it is more sloth muscle than jackrabbit muscle.