Recreating the Cotinga's Color
Without a doubt, there are many beautiful sights in Nature, and among these is the spangled cotinga, whose beauty has been vexing humans for some time. This particular bird has a lovely blue color, and unlike paintings and clothes, the color never fades. We know why this is but finally researchers at Harvard University have found a means to replicate it that could lead to many more, permanent colors.
The pigments we use in our dyes and paints work by absorbing all but one color of light, but that absorbing of energy eventually causes the pigment to fade. The cotinga color never fades because it is a structural color, caused by a nanostructure that only reflects one color to our eyes. While we understand how structural color works, reproducing it is very difficult as it can require a material's molecules to have a special pattern. The Harvard researchers built upon research performed at Yale University by creating colloidal suspensions of microcapsules. Within each microcapsule are smaller particles with a disordered pattern, but as the microcapsules dry, the distance between those particles shrink. That distance is what determines what structural color is reflected, and the researchers observed it shift through the spectrum, as the microcapsules shrunk.
The hope is that this technology could be used to create permanent colors for us to enjoy, perhaps as full color displays on flexible plastics. Also, as structural color is dependent on the structure of a material and not the material itself, it could potentially be used to replace some toxic inks.
Source: Harvard University