Color-changing material indicates chemical weapons exposure
Tiny polymer spheres are melted into a shimmery sheet; technology could have appplications in food safety and anti-counterfeiting efforts
A debate has raged for years about whether the Army’s new pixilated camoflauge is better or worse than the traditional printed standard issues. How will the troops react when they hear about this? Scientists at the University of Surrey have developed a clothing material that changes color when exposed to a chemical weapon. The technique — which also has applications in the food safety business — relies on the manipulation of tiny polymer spheres melted into sheets of biodegradable plastic. “The colors are set primarily by the size of the spheres,” explained professor Jeremy Baumberg. “If you look at different angles you get different colours. What we have also discovered is that if you add tiny amounts of nanoparticles of carbon, for example, you get a very strong, metallic green colour. This is the effect we are trying to understand.”
The British defense research lab, DSTL, is supporting the effort with a £200,000 grant. In addition to creating freshness-indicating food packaging, the technology could also be used to create new securiuty features in banknotes. Still, Baumberg admits that the technology is not ready for primetime, the main reason being that he does not yet understand exactly why cetain chemicals create certain colors in the film. “We need to prove it can be made in the specification you want, on demand, completely predictably,” he said. “The scattering inside this periodic set of spheres is very different to normal light scattering, so we are trying to understand that, as sometimes it works better than others
