Researchers develop method for 3D printing of the entire color spectrum
Researchers at ETH Zurich have developed a method based on a butterfly, with which they can reproduce the entire color spectrum with 3D printing. The color printing method could be useful for authentication purposes on banknotes or in the manufacture of flexible screens. We present the new method in more detail.
display
Inspired by the wings of the uniform butterfly, researchers at ETH Zurich were able to Cynandra opis, produce artificially colored nanostructures with 3D printing. The wing of the particularly butterfly species Cynandra opis stands out with bright colors. The colors are not based on pigments but are structural. They are created by intricate nanostructures on the surface of the wings. By deflecting and refracting visible light, Cynandra opis’ wings enhance certain color components. This results in a gem-like shine.
They published their study in an article in the journal Advanced Materials entitled “Replication of Cynandra opis butterfly structural color for bio-inspired Bigrating color filters“. Using a modified 3D printing process, researchers at the University of Illinois Urbana-Champaign have developed an approach to 3D printing multiple colors with a single ink.
Details about the work
Biochemical engineering professor Andrew deMello led the research group at ETH Zurich, which succeeded in recreating the naturally occurring structures using tailor-made nanoprinting technology.
Xiaobao Cao, first author of the study, explains:
“The efficient nanostructures, particularly on the wings of Cynandra opis, lent themselves well to reconstruction using 3D printing.”
Viewed under the microscope, the wings of Cynandra opis consist of a two-dimensional lattice of rods stacked on top of each other. The distance between the rods is between 0.5 and 1 micron.
3D printing identical rod lattices with different constants and heights ranging from 250 nanometers to 1.2 micrometers showed the researchers that they can produce virtually any color in the visible spectrum. Some of the hues obtained in the study do not even come from the wings of Cynandra opis. The nanostructures were printed with different materials such as transparent polymers using a 3D printer.
Stavros Stavrakis, co-author of the study, said:
“This made it possible to backlight the structure to bring out the colour. For the first time we have succeeded in creating all the colors of the visible spectrum as structural colors in a translucent material.”
possible applications
The ETH team printed a tiny 2 x 2 micron image made up of uniform color pixels. Similar tiny images could be used on banknotes and other documents for authentication purposes. Since 3D printing is also possible with transparent materials, the colors could also be used as color filters for optical devices. DeMello’s research group has focused on the Development of microfluidic systems specialized. With the current work, systems for chemical and biological experiments could be miniaturized.
The ETH team also states that large-scale production of the color pixels would be feasible. That would enable new types of high-resolution color displays or flexible screens. For the researchers, the 3D-printed structural colors are an adequate alternative to the pigments used in printing and painting. Not only will they last longer due to resistance to UV-induced fading, but they will also offer a better environmental footprint.