The PhotoChromeleon colour scheme in action. Image: MIT CSAIL
A breakthrough using special ink and light brings us closer to giving any object chameleon powers.
Researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have revealed a new reprogrammable ink that lets objects change colours when exposed to UV and visible light sources.
Writing in a paper, the researchers dubbed the technology ‘PhotoChromeleon’. It uses a mix of photochromic dyes that can be sprayed or painted on to the surface of any object to change its colour, and is both fully reversible and repeatable an infinite number of times.
Highlighting some examples, they said that it could be best applied to objects such as a mobile phone case or a shoe.
“This special type of dye could enable a whole myriad of customisation options that could improve manufacturing efficiency and reduce overall waste,” said CSAIL postdoc Yuhua Jin, lead author of the study.
“Users could personalise their belongings and appearance on a daily basis, without the need to buy the same object multiple times in different colours and styles.”
The ink was created by mixing cyan, magenta and yellow photochromic dyes into a single sprayable solution, eliminating the need to painstakingly 3D print individual pixels as seen with the researchers’ previous research, dubbed ColorMod.
‘Countless resources could be preserved’
By learning how each dye interacts with different wavelengths, the researchers could control each colour channel through activating and deactivating with the corresponding light sources. Three different lights with different wavelengths were used to eliminate each primary colour separately.
For example, magenta would absorb green light and become deactivated, with just yellow and cyan remaining. This combination would leave green as the only colour remaining. Once an object is coated, the PhotoChromeleon user places it in a box with a projector and UV light.
The resulting UV light saturates the colours from transparent to full saturation and the projector desaturates the colours as needed. Once the light has activated the colours, the new pattern appears. Depending on the shape and orientation of the object, the process takes anywhere between 15 and 40 minutes.
MIT’s Stefanie Mueller said: “By giving users the autonomy to individualise their items, countless resources could be preserved, and the opportunities to creatively change your favourite possessions are boundless.”
The next step of the research plans to see collaborations with material scientists to create improved dyes.
