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Case researchers developing self-healing polymers

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June 3, 2013

CINCINNATI — Researchers at Case Western Reserve University have developed materials that can heal themselves.

A team, led by Case Western professor Stuart Rowan, is working on structurally dynamic polymers that respond to stimuli like ultraviolet light.

Rowan also is director of the university's Institute for Advanced Materials.

The adaptive polymer systems rely on reversible chemistry to prompt a response at the molecular level. The materials are called metallo-supramolecular polymers or MSPs and are made by essentially binding metal ions and polymers.

The film material acts like a normal polymer until it's exposed to ultraviolet light (no more intense than the lamps dentists use when filling teeth). When exposed to light, the polymer system absorbs heat locally. This heats up a reversible bond and the result is essentially a decomplexation and reorganization of the system, explained Rowan, in a presentation at Antec 2013 in Cincinnati.

In simpler terms: you can shine a light on a scratched film and the scratch disappears, like it was never there in the first place.

Once the material has been healed, you can't find the scratch again, Rowan said, adding that the material can be scratched and healed repeatedly.

The team has also worked on similar technology to make films with shape memory. For example, a film wrapped around a tube and exposed to ultraviolet light will hold a spiral shape, until it's dropped in water where it springs back into a flat shape.

They've also developed material that combines both photo healing and shape memory properties, he said. You could use light to make the film take on a particular shape, then cause it to flatten out, then expose it to light again to jump back into shape. The films have been reprogrammed to stay coiled.

Now that the research team has proved their process works, they're starting to design materials that are more commercially available, Rowan said.

He emphasized that it's are a relatively new technology and more understanding is needed before commercializing.