Scientists produced "polymer opals" that scatter light in intense colors. These intriguing materials change colors when stretched or twisted.
Stretching the new material will transform its color into the color spectrum's blue range while compressing it will shift it towards the red range. Releasing the material will coax it back to its original, starting color.
University of Cambridge researchers also managed to manufacture these materials on industrial scales. This suggested that the new materials can have a wide range of applications from banknote security features to smart clothing.
Other potential applications could include heat-reflective coatings for buildings, footwear and packaging.
For the study, they utilized a new technique called Bend-Induced-Oscillatory-Shearing (BIOS) to produce hundreds of meters of polymer opals.
Some of nature's brightest colors including the ones in butterflies and opal gemstones can be traced to their innate microstructures that follow a systematic order. This is what the Cavendish Laboratory-based researchers tried to artificially recreate.
"Finding a way to coax objects a billionth of a meter across into perfect formation over kilometer scales is a miracle. But spheres are only the first step, as it should be applicable to more complex architectures on tiny scales," said senior author Professor Jeremy Baumberg.
Producing the polymer opals started with growing barrels of transparent plastic nano-spheres. Each of these plastic nano-spheres has a solid core and a sticky exterior.
The team allowed these nano-spheres to dry out into a gelatinous mass. The team bent sheets that contain a sandwich of these nano-spheres using successive rollers, which then produced systematically-arranged stacks.
The research team changed the sizes of the initial nano-spheres to create different colors. The material's rubber band-like consistency allows the spaces between the nano-spheres to change. This causes the material to change colors when stretched or twisted.
"It's wonderful to finally understand the secrets of these attractive films," said lead author and Ph.D. student Qibin Zhao.
Cambridge Enterprise is helping to look for commercial opportunities for the new material. So far, over 100 companies have reached out to the University's commercialization arm.
The research was published in the Nature Communications journal on June 3.
