Nov
02
2007

Nanotechnology sometimes borrows from nature.

Morpho butterfly: Pigments don’t cause these butterflies’ intense colors. Instead, super-small lattice-like structures on the wings reflect only certain wavelengths of light (or color). And the colors shift with your perspective. (Photo courtesy Lionoche, through Flickr)
Morpho butterfly: Pigments don’t cause these butterflies’ intense colors. Instead, super-small lattice-like structures on the wings reflect only certain wavelengths of light (or color). And the colors shift with your perspective. (Photo courtesy Lionoche, through Flickr)

Super-small, light-reflecting structures—instead of pigments—create a morpho butterfly's intense, iridescent wing color. Scientists are developing nanomaterials with similar properties.

Zoom in on a butterfly's wing
Zoom in on a butterfly's wing

If you used a special microscope to look at these butterfly wings, you’d see tiny scales made up of thin layers of transparent wing material with nanoscale gaps between them. Light waves bouncing off the bottom surfaces interfere with waves reflecting from the tops. Most light waves are cancelled and only certain wavelengths—or colors—bounce back to your eyes. The more light in the environment, the brighter the color.

Wing structures: These complicated structures on butterfly wings manipulate light to control the color that we see.
Wing structures: These complicated structures on butterfly wings manipulate light to control the color that we see.

How do transparent thin films create color?: Scientists haven't yet created materials that work exactly like the butterfly wings. But layers and layers of transparent, super-thin films--each with a different index of refraction--can be tuned so that they only reflect specific wavelengths of light (o
How do transparent thin films create color?: Scientists haven't yet created materials that work exactly like the butterfly wings. But layers and layers of transparent, super-thin films--each with a different index of refraction--can be tuned so that they only reflect specific wavelengths of light (o

Scientists are developing all sorts of products that, like the butterfly wings, use layers of transparent materials with nanoscale spacing between them to manipulate light and create color. With them, we can create computer and cell phone displays, fabrics and paints that change color, optical devices that improve telecommunications systems, and films that reflect much more light than glass mirrors. Can you imagine other uses?

Your Comments, Thoughts, Questions, Ideas

Liza's picture
Liza says:

Iridescent dichroic—or “two-color”—glass doesn’t actually contain any color. Instead, many super-thin layers of a special coating on the glass let only certain wavelengths of light pass through it while reflecting others.

Dichroic glass: These clear glass tiles—part of an art installation in the Science Museum of Minnesota’s lobby—appear yellow or blue according to your perspective. (Photo courtesy Chad Fust, courtesy Flickr)
Dichroic glass: These clear glass tiles—part of an art installation in the Science Museum of Minnesota’s lobby—appear yellow or blue according to your perspective. (Photo courtesy Chad Fust, courtesy Flickr)

posted on Fri, 11/02/2007 - 10:41am
Liza's picture
Liza says:

Researchers at 3M are creating thin films that, like the butterfly wings, reflect only specific wavelengths of light. Each film—color, or mirror—is actually a stack of many super-thin transparent layers.

The decorative "color" films, each made up of about 225 layers, are tuned so they reflect a fraction of the visible spectrum of light.

The mirror film, made up of about 450 layers, reflects all (or almost all) colors. Films like this one reflect much more light than glass mirrors and can be used in place of them.

posted on Fri, 11/02/2007 - 10:48am
Liza's picture
Liza says:

QUALCOMM’s MEMS computer and cell phone displays also use thin film technology to generate colors. Each pixel of the display is made up of tiny structures—a thin-film stack and a reflective membrane on a glass plate—that reflect specific wavelengths of light according to the spacing between the stack and the membrane.

What do butterflies and cell phones have in common?: (Image courtesy Qualcomm)
What do butterflies and cell phones have in common?: (Image courtesy Qualcomm)

MEMS vs. conventional display: The phone on the right has a MEMS display, and the phone on the left doesn't. The photo was taken in sunlight; the brighter the ambient and natural light, the clearer the MEMS display. (Photo courtesy Qualcomm)
MEMS vs. conventional display: The phone on the right has a MEMS display, and the phone on the left doesn't. The photo was taken in sunlight; the brighter the ambient and natural light, the clearer the MEMS display. (Photo courtesy Qualcomm)

posted on Fri, 11/02/2007 - 10:56am
Anonymous's picture
Anonymous says:

uhmm ok

posted on Fri, 11/02/2007 - 11:29am
Liza's picture
Liza says:

The iridescent colors of the ruby-throated hummingbird (October 2007 "Object of the Month") come from tiny structures on the surfaces of their feathers that reflect only certain wavelengths of light. Pigment-wise, most of the feathers are actually brown or black.

Peacock feathers are iridescent for the same reason.

posted on Fri, 11/02/2007 - 1:17pm
Thor's picture
Thor says:

This sounds a lot like the technology being incorporated into the new U.S. $100 bills. Little threads with mirror-like properties will make Ben Franklin move back and forth when you tilt the bill back and forth, letting you know it's not a counterfeit.

More details are on this previous blog post.

posted on Fri, 11/02/2007 - 4:21pm
diamond2008's picture
diamond2008 says:

I love butterflies they are so beautiful!!!!

posted on Fri, 05/23/2008 - 10:07am
dara's picture
dara says:

yes, i totally agree! how to they get their patterns? its amazing

posted on Fri, 05/23/2008 - 11:03am
SLC's picture
SLC says:

How are they able to get different color on their wings or how can they get different pattern on their wings? Well that is kind of werid how they can do that. Is it what they eat? Butterfiles are really cool to look at and see them fly around.

posted on Mon, 12/08/2008 - 1:08pm

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