The researchers have worked on a formula that allows polymers to change shape
New advances in science that enable shapeshifting polymers are being held as a “scientific breakthrough”, with the potential to lead to a new generation of materials for innovations in medical, electronics and other fields.
A research team, led by Prof. Xie Tao of the College of Chemical and Biological Engineering at Zhejiang University, has unveiled a new shape memory polymer that can change its permanent shapes multiple times—remembering its current shape as well as new ones. This is believed to be a big step up from existing self-folding polymers, enabling intricate configurations and features.
The research paper, entitled “Shape Memory Polymer Network with Thermally Distinct Elasticity and Plasticity”, was published in Science Advances on January 8.
In the recent past, material scientists have come up with polymers that change from one shape to another when heated or cooled—the main drawback for them has been that they can only be programmed to take one or two shapes.
In this new effort, the researchers have come up with a polymer that is capable of forming itself into many different shapes, by combing two ingredients—one that has elastic deformation properties and the other that has plastic deformation properties. Current polymers tend to have the former property, which is useful for some limited applications. But what has really been needed, the team notes, is a polymer capable of plastic deformation, where it is re-shaped permanently without having to resort to melting—due to covalent bond exchange.
To make the polymer, the researchers added the chemical 1,5,7-triazabicyclo[4.4.0]dec-5-ene to an elastic material known as crosslinked poly (caprolactone) , the result was a plastic that had a low transitive temperature (55˚C) and a high deformation temperature (130˚C).
The new material can be programmed by physically pushing the material into different shapes at different temperatures. To make them come about on demand, the material is subjected to the temperature that corresponds with the shape that is desired. The group created several such polymers and demonstrated that it was possible to cause the same piece of material to fold itself into first one shape, then another—in one such example a material was first caused to revert to an origami boat and then to revert to an origami flower.
The team reports that in addition to a high degree of programmability the polymer also demonstrated toughness—it could be caused to change in to multiple different shapes over and over again without cracking or degrading. They believe the new material could likely be used in medical applications, in shape-shifting electronics, or potentailly aboard spacecraft.