As an increasing number of lightweight, load-bearing composite materials make their way into industries like automotive manufacturing, shipbuilding, and aircraft construction, there’s a growing need to develop new methods for early detection of damage to — or even potential failure of — these yet-understudied materials.
With the goal of providing such a solution, scientists from the Complex Materials Group at ETH Zurich have created a lightweight material that uses a color change to signal internal deformation and thus possible material failure at an early stage. Made up of individual layers, the new laminate layer is translucent and break-resistant, yet very lightweight.
As explained by Futurity, the laminate is composed of alternating layers of a plastic polymer and artificial mother-of-pearl. The latter is modeled after the biological structure of the mussel shell, and consists of countless glass platelets arranged in parallel. These platelets are compacted, sintered, and solidified using a polymeric resin, which makes the layer extremely hard and break-resistant.
On top of the first layer sits another one made of a polymer to which the researchers added an indicator molecule synthesized specifically for the task at hand. The molecule is activated as soon as the polymer experiences a strain, and this changes its fluorescence. The more the material stretches, the more of those molecules are activating, increasing the fluorescence.
“We used fluorescent molecules because you can measure the increase in fluorescence very well and you don’t have to rely on subjective perception,” says Tommaso Magrini, lead author of the study.
The fluorescence serves as an indicator, allowing the researchers to identify overstressed areas within the composite material even before fractures occur. This, in turn, can help detect vulnerable areas in a structure, thus preventing a disaster. Possible applications for the laminate include load-bearing structures of buildings, aircraft, or vehicles, where it’s essential to detect a failure at an early stage.
Study Source: ACS Applied Materials and Interfaces — Tough Bioinspired Composites That Self-Report Damage
