Colour patches indicate soldiers’ blast exposure level

Researchers at the University of Pennsylvania have developed a colour-changing patch that could be worn on soldiers’ helmets to indicate how badly they may have been exposed to blasts from explosives.

’We wanted to create a “blast badge” that would be lightweight, durable, power free and, perhaps most importantly, could be easily interpreted, even on the battlefield,’ said Dr Douglas Smith, professor of neurosurgery at at the University of Pennsylvania School of Medicine, and School of Engineering and Applied Sciences.

To do so, Smith and his team built the badge from nanoscale structures whose make-up preferentially reflects certain wavelengths of light. The structures are designed to break apart when exposed to a blast shockwave and, when they do, the material’s reflective properties are modified, which in turn causes a substantial colour change.

The material is designed so that the extent of the colour change corresponds to the intensity of the blast. Next, the researchers aim to calibrate the colour change to the intensity of exposure to provide an immediate indication of the potential harm to the brain from such blasts and the subsequent need for medical intervention.