Scientists from the Okinawa Institute of Science and Technology Graduate University (OIST) have created a stress-detecting ‘smart’ polymer that shines brighter when stretched.

They hope to use it to measure the performance of synthetic polymers and track the wear and tear on materials used in engineering and construction industries.

The scientists developed this polymer by incorporating ‘copper complexes’ — structures formed by linking copper atoms to organic (carbon-containing) molecules — into a polymer called polybutylacrylate, which is made from a chemical used to synthesize acrylic paints, adhesives and sealants.

The copper complexes, which link the polybutylacrylate chains together, naturally glow when exposed to ultraviolet light, but when the polymer is stretched, the copper complexes emit light at a greater intensity, leading to a brighter glow.

Ayumu Karimata, first author of the study and a post-doctoral scholar at OIST (www.oist.jp), says he hopes that the acrylic polymer could eventually be adapted to create a stress-sensing acrylic paint.

“This could have valuable applications as a coating for different structures, such as bridges or the frames of cars and aircraft.

"As we can see even from the direct visualisation of the polymer, stress is applied across a material in a non-uniform way.

"A stress-sensing paint would allow hot-spots of stress on a material to be detected and could help to prevent a structure from failing.”