Now, your photographs too can change colour when stretched: Report
The research published in Nature Materials journal, gives the first scalable manufacturing technique for producing detailed, large-scale materials with “structural colour”.
A new study published in MIT News reveals that the MIT engineers have ‘resurrected and repurposed’ a traditional photographic technique to produce a film which modifies its colour on elongating. The research inspired by nature “produced stretchy films printed with detailed flower bouquets that morph from warm to cooler shades when the films are stretched”, it noted.
What is the inspiration for the research ?
The researchers who got the work published in Nature Materials journal have taken inspiration from the environment to develop this optical material. They examined light-reflecting properties in mollusc shells, butterfly wings, and other iridescent organisms. They researched how the microscopic surface structure of these organisms helps to glimmer and vary the colours. These structures operate as miniature coloured mirrors angled and layered to reflect light.
However, duplicating this was a challenge as some experiments ‘have produced small samples with precise nanoscale structures, while others have generated larger samples, but with less optical precision’. The team then wrote, “an approach that offers both [microscale control and scalability] remains elusive”.
How does the technique work?
The team printed large-scale images onto elastic materials by applying Lippmann photography, a 19th-century Nobel Prize winning colour photography technique, to modern holographic material. Holography is a technique that produces 3D pictures by overlaying two light beams onto a physical material. Using modern holography material hastened up the photography technique. The light-sensitive materials were exposed to photons, cross-connecting it to form coloured mirrors and developing a film whose colours are sensitive to strains.
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What is the peculiarity of this approach?
It is possible to manufacture colour changing materials by adding chemical additives or dyes. However, the research result gives the first scalable manufacturing technique for producing detailed, large-scale materials with “structural colour”. Structural colours are those that are attributed to its microscopic structure. Illustrating the difficulty linked with the research, Benjamin Miller, a graduate at MIT, told MIT News, “Scaling these materials is not trivial, because you need to control these structures at the nanoscale”.
What are the applications of the research ?
Utilizing this technique, One can encrypt a message in the film, which will only be visible on stretching. Ranging from minimalist usage in developing attractive colour changing textiles, sporting a swimsuit that changes shade with each passing lap to crucial application in touch sensing robots and manufacturing of pressure-monitoring bandages, this colour-shifting material has various applications.