A polymer-based material that changes colour when smashed has been developed by American researchers, potentially paving the way for future brain-injury detecting helmets.
Whether it's soldiers or American football players, there are quite a few professions at risk of receiving heavy blows in their heads. Despite wearing protective headgear, many frequently suffer devastating injuries which may not be immediately obvious. Some consequences of head trauma can occur years after the actual incident took place including memory loss, headaches and dementia.
The material developed by a team from the University of Pennsylvania could in the future indicate danger right at the time of the incident. A simple patch of the material based on photonic crystals integrated into a helmet could provide warning by changing colour according to the force of the impact.
“The film can show the colour change depending how much and how quickly the force is applied,” said Younhyun Cho who developed the self-assembling polymer.
Inside the material, chains of molecules bind together if force is applied, producing crystals of different colours. For example, a force of 30 millinewton, equivalent to a sedan crashing at 80 miles an hour into a brick wall changes the crystal from red to green. A force of 90 milinewtons turns the polymer purple.
"If the force was large enough and you could easily tell that, then you could immediately seek medical attention," explained Shu Yang, another member of the team.
Knowing the actual force of each impact could help prevent debilitating consequences of head trauma in sportsmen who suffer such blows in their heads on a regular bases.
The major advantage of the lightweight material, the researchers said, is the fact it doesn’t require an external power source and would thus be easy to integrate into helmets.
The researchers are now developing a new manufacturing method that could drive down the cost of the material, required for commercial use.