The technique makes use
of structural colors, which have different properties than the ink dyes used for standard printing.
But finding a simple way to generate these
complex structural colors — a technique that can be scaled up and used to create many different hues — has been a tricky task.
We started looking at the skins of closely related birds, and we had another surprise: Yes, they had
structural colors made by collagen fibers, too, but the collagen fibers there were not arranged in a perfect crystalline order.
Our research focuses on the way in which animals use crystalline materials to manipulate light, for example, to
produce structural colors used in camouflage and display [1, 3].
The fossils are the earliest known examples of insects
displaying structural color — that is, color produced by light bending around microscopic structures, rather than light being absorbed and reflected as with a pigment or a dye.
Structural colors rely exclusively on the density and shape of the material rather than its chemical properties.
Thomas said one of his former Ph.D. students at MIT, Cheolmin Park, who is now a professor at Yonsei University, wanted to collaborate on developing printable and rewritable
copolymer structural colors.
Just
like structural color in the animal kingdom is used to attract a mate, evade predators, or even communicate over long distances, here iridescence is used to confound and seduce the viewer.
This effect,
called structural color, has also been found in chameleons that can «tune» nanocrystals in their skin to change color the way tuning a guitar changes its pitch, as reported in 2015 in Nature Communications.
They're one of the key ingredients in a new way to craft a spectrum
of structural colors — hues created when light interacts with special nanostructures.
Structural color is common in bird feathers and butterfly wings today, but finding such features in the fossil record can be tricky.
Fossil scales illuminate the early evolution of lepidopterans and
structural colors.
Before that, nobody had really created intellectual tools for understanding how less ordered materials could produce
these structural colors.
Such disorder in nature's
structural color (versus pigments) has shown up before, as in obviously jumbled color - trick structures in bird feathers.
But altering the spacing of the nanoparticles in the ball affects how the particles scatter light, generating a spectrum of
structural colors, says study coauthor Ali Dhinojwala, a polymer scientist at the University of Akron in Ohio.
Structural colors are a longer - lasting alternative to chemical pigments, which lose all pizazz when they break down.
Scientists are now peeking inside the chrysalis to watch
these structural colors form as a living butterfly develops.
But in the past few years, paleontologists have found a way around this obstacle through the phenomenon of
structural color.
These structural colors were printed on the same sheet of paper coated with copolymers through the application of ammonium persulfate and ethanol.
Structural colors are determined by the selective reflections of certain colors at certain angles.
The researchers found that they could use a single, colorless, water - based ink based on ammonium persulfate (APS) to control how the copolymers cross-link in various locations, which impacts their subsequent thickness and hence
the structural colors that are reflected.
Fossil specimens of adult macrolepidopterans often exhibit light - and dark - toned areas on their wings [14] and can retain ultrastructural details of their scales [15]; preservation of pigmentary or
structural colors has not been reported.
Now, researchers at the University of Michigan have found a way to lock in so - called
structural color, which is made with texture rather than chemicals.
The blue of a bluebird delights us thanks to
structural color — the color is generated by light interacting with a feather's 3 - D arrangement rather than by actual blue pigment.