Once again, scientists are inspired by nature in their work and here, intensively so. Authors Yuhua Jin, Isabel Qamar, Michael Wessely, Aradhana Adhikari, Katarina Bulovic, Parinya Punpongsanon and Stefanie Mueller explain their recent work in Photo-Chromeleon: Programmable Multicolor Textures Using Photochromic Dyes.
Like a charm. the chameleon goes on for centuries, no one has ever been able to repeat the magic of their skin changing color. The MIT Computer Science and Artificial Intelligence Lab team is touching this phenomenon to its latest 3D printing endeavors, creating reprogrammable ink that changes colors when exposed to UV and other light sources. The PhotoChromeleon system consists of multiple dyes sprayed onto the object's surface, allowing it to change color as needed.
"By mixing the photochromic cyan, magenta and yellow (CMY) dyes in one solution and using the different absorption spectra of each dye, we can control each color channel in the solution individually," the authors state. "Our approach can transform single-material manufacturing techniques, such as coating, into high-resolution multicolor processes."
We can create reprogrammable multi-color textures from a single material. (a) We mixed CMY photochromic dyes together to create our multicolor ink. (b) After covering the subject, we use (c) a UV light source and a projector to control each color channel on a pixel-by-pixel basis, resulting in multi-color, high-resolution textures that can be re-applied repeatedly.  The potential for personalization is exciting, allowing it to be used not only in the natural environment (where the color remains after application because of its bi-stable nature), but also other applications such as car paint, phone cases and even fashion items such as shoes .
"This special type of dye could allow for numerous customization options that could improve production efficiency and reduce overall waste," says CSAIL postdoc Yuhua Jin and lead author. "Consumers could customize their belongings and appearance on a daily basis without having to buy the same object several times in different colors and styles."
(a) CMY inks mixed together achieve a black that matches (b) CMY color pattern.
Advancing from the latest ColorMod system, PhotoChromeleon ink allows users to create complex patterns and even "sweep the landscape" in multiple colors. The user interface creates designs and models and then the program transfers it to the object. Once an object is covered and then placed under ultraviolet light, the colors range from transparent to 'full saturation' and can be de-energized as desired, taking the entire process for the user from 15 to 40 minutes. Designs can also be easily erased with UV light.
"By empowering users to customize their items, countless resources can be preserved and the possibilities to creatively change your favorite possessions are endless," says MIT professor Stephanie Muller.
There are still some limitations in the color gamut, and in some cases researchers need to reconcile just to get closer to a certain hue; however, they plan to work with material scientists to complete the full color palette.
"We believe that incorporating new, multiphotochrome inks into traditional materials can add value to Ford products by reducing the cost and time required to produce automotive parts," says Dr. Alper Kiziltas, Sustainability and Technology Specialist Ford's emerging materials. "This ink could reduce the number of steps required to produce a multicolor part or improve the color's resistance to weathering or UV degradation. One day we may even be able to customize our vehicles at a whim. "
Gene co-authored the document with CSAIL PhD students Isabel Kamar and Michael Wesley. Former MIT UROP students Aradhana Adhikari and Katarina Bulovic contributed as well as an MIT fellow and current assistant professor of engineering at Osaka University, Parina Punponsanon, and Stephanie Muller.
Former MIT UROP student Aradhana Adhikari received the Morais and Rosenbloom Best UROP Award for his contributions to the project.
Although it is a complex and useful system with potential for use for 3D printing enthusiasts around the world, nature has been inspired by various projects from the creation of conductive parts for recyclable liquid polymers, replication of other complex structures and others. What do you think about this news? Tell us your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.
(a) Applying the photochromic coating and (b) the resulting coated object after UV activation.
The same shoe with two different textures to match the user's daily wear.