Now, colour-changing patch that detects exposure to explosive shock
By ANITuesday, November 30, 2010
WASHINGTON - University of Pennsylvania researchers have developed a colour-changing patch that could be worn on soldiers’ helmets and uniforms to indicate the strength of exposure to blasts from explosives in the field.
Future studies have aimed to calibrate the colour change to the intensity of exposure to provide an immediate read on the potential harm to the brain and the subsequent need for medical intervention.
“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,” said senior author Douglas H. Smith.
“Similar to how an opera singer can shatter glass crystal, we chose colour-changing crystals that could be designed to break apart when exposed to a blast shockwave, causing a substantial colour change,” he said.
The badges are comprised of nanoscale structures, in this case pores and columns, whose make-up preferentially reflects certain wavelengths. Lasers sculpt these tiny shapes into a plastic sheet.
Yang’s group pioneered this microfabrication of three-dimensional photonic structures using holographic lithography.
“We came up the idea of using three-dimensional photonic crystals as a blast injury dosimeter because of their unique structure-dependent mechanical response and colorful display,” she explained.
Although very stable in the presence of heat, cold or physical impact, the nanostructures are selectively altered by blast exposure. The shockwave causes the columns to collapse and the pores to grow larger, thereby changing the material’s reflective properties and outward colour. (ANI)
