Researchers from the AGH University of Science and Technology in Kraków, working with partners from Japan and India, have developed a smart material that changes colour when subjected to mechanical stress. The invention could be used to prevent structural failures, the scientists said.
According to AGH UST, the material glows greenish-yellow under normal conditions. When stressed, it turns red, and the process is reversible: adding a solvent restores the original colour.
Professor Konrad Szaciłowski’s team in Kraków provided the theoretical models that explained the mechanism behind the colour shift. “It is precisely this combination of expertise – synthesis in Japan, spectroscopy in India, and molecular modelling in Poland – that has enabled us to create something with real implementation potential,” the university said in a statement.
The researchers found that the material could help monitor stresses in building structures and warn of potential failures. “It would be enough to track stresses in building structures and address changes in time. For example, the colour of paint on a bridge could change with changes in stress within its structure,” AGH UST explained.
Currently, no such real-time monitoring solutions are in place.
Describing how the compound works Szaciłowski said: “Each particle contains one lock and two keys, or vice versa, meaning it is composed of several modules that fit together and are separated. In a crystal, we have a situation where the ‘key’ of one molecule fits the ‘lock’ of another. This interaction creates a material with a specific colour. Additionally, it is characterized by strong luminescence, so when excited by ultraviolet light, it emits greenish-yellow glow.
“When mechanical damage occurs to the crystals, the molecules shift relative to each other, and the interactions are destroyed. Other interactions form, however, and their appearance causes the colour change from yellowish-green to red,” he added. (PAP)
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