Ultrathin exterior scales of beetles create brilliant whiteness by scattering a wide spectrum of visible light wavelengths.

Beetles in the Cyphochilus genus achieve their striking white coloration not through chemical pigments, but through a disordered tangle of 250 nm-diameter filaments in their scales. The fibers are sparsely packed with just the right number of voids, giving rise to a thorough scattering of light that causes the brilliant whiteness. The secret is not in the material itself, but the structure—the way the meshwork of fibers and voids scatters the light. Unlike colors, which can be created by using highly ordered structures to scatter light, white is created by a random, simultaneous scattering of light.

The beetle’s whitening effect is accomplished without benzene rings, and in a fully biodegradable and common material—chitin. Mimicking this physical effect in any kind of coating or additive is holds great promise for a number of applications to reduce use of toxic chemicals or reduce energy consumption.

Image: Andrea Leggitt / The Biomimicry Institute / 

Simplified rendering of how the random network of microscopic structures within the beetles shell scatter light, resulting in a stark white appearance.

Last Updated August 23, 2016