University of Pennsylvania scientists say calibrating the color change to the intensity of the explosion could provide immediate information on possible injury to the brain and the need for medical intervention, a university release said.
"We wanted to create a 'blast badge' that would be lightweight, durable, power-free, and perhaps most important, could be easily interpreted, even on the battlefield," Douglas H. Smith, professor of neurosurgery, said.
Blast-induced traumatic brain injury has been described as the "signature wound" of the current wars in Iraq and Afghanistan.
"Diagnosis of mild traumatic brain injury is challenging under most circumstances, as subtle or slowly progressive damage to brain tissue occurs in a manner undetectable by conventional imaging techniques," D. Kacy Cullen, assistant professor of neurosurgery, says.
The "blast badges" are made up of nanoscale structures whose make-up preferentially reflects certain wavelengths.
The shock wave of an explosion alters the structures, changing the material's reflective properties and therefore its outward color.
"Similar to how an opera singer can shatter glass crystal, we chose color-changing crystals that could be designed to break apart when exposed to a blast shock wave, causing a substantial color change," Smith says.
The material is designed so the extent of the color change corresponds with blast intensity.