My January 2012 NISE (Nanoscale informal science education) Net newsletter (The Nano Bite) features a new video, this one about the Blue Morpho butterfly which shows the butterfly wings at various magnifications. (I most recently wrote about the butterfly in my Oct. 14, 2011 posting on colour, nanostructures, and nature.)
Zoom into a Blue Morpho Butterfly (with narration) from NISE Network on Vimeo. You can find the video and additional information in the catalog.
I’ve read about the nanostructures but I’ve never seen them before and was thrilled about it since there’s a Jan. 5, 2012 news item on Nanowerk regarding bioinspired colour and some of the challenges scientists face as they try to incorporate this inspiration into materials,
Nature’s ability to actively control color has led scientists to integrate structural color into the design of modern technologies. But how do scientists accurately mimic nature for such applications?
Hiroshi Fudouzi at National Institute for Materials Science (NIMS) in Japan describes the challenges facing materials scientists for the realization of photonic crystals based on design of bioinspired structural color.
The review paper, published in Science and Technology of Advanced Materials (“Tunable structural color in organisms and photonic materials for design of bioinspired materials”) [article available in open access journal], focuses on active structural color and covers the following aspects of structural color …
From the introduction to Fudouzi’s paper (I have removed reference numbers, please check the paper for all the citations and reference numbers),
Iridescence is a structural color formed without using pigments, dye or luminescence. It originates from
spectrally selective reflection of visible light from a periodic modulation of refractive index. We can observe the structural color in natural life forms, for example, in peacock feathers, outer shells of jewel beetles, wings of Morpho butterflies and many other insects. A previous review summarized the multilayer interference of light in aquatic organisms, particularly in fish scales. Multilayer interference is also the major topic of this paper. Structural color in nature is used in camouflage, intimidation (warning), display and communication, and there have been recent discoveries in this area from the viewpoint of photonic crystals. However, the structural color of life forms cannot be expressed using a simple interference model, and its origin, particularly in butterflies, remains an active research topic in biology and physics.
The scales of some fishes and epidermises of insects can change their structural color.The blue color of Morpho butterfly wings is caused by their periodic nanostructure. It can be changed by varying the refractive index n, for example, from blue to green by soaking in acetone (n = 1.362). After the wings are dried, their color returns to original. This is an example of passive color change, and in this review, we focus on active structural color in organisms, that is, voluntary color changes in some groups of tropical fish, octopus, squid and beetle in response to external stimuli. Revealing their mechanisms may provide hints for the fabrication of new photonic materials with tunable structural color. Such bioinspired or biomimetic materials are a new trend and an emerging technology (p. 2)
One of the fish that Fudouzi examined is the blue damselfish. Here’s a video of someone’s home aquarium featuring the fish,
I did go looking for some of the challenges that bioinspiration brings,
As outlined in this review, bioinspired approaches are useful for the design of photonic materials. A humidity sensor based on 3D opal photonic crystals was fabricated on the basis of the nanoporous structure of the Hercules beetle. This sensor changes its color from blue to red at high humidity; however, it is yet unselective to the carrier gas. (p. 8) [emphasis mine]
If you are interested in more information about Dr. Fudouzi and his work, you can check at his page on the National Institute for Materials Science (NIMS), Learning from Nature Cluster website.