Nanostructures for Coloration (Organisms Other Than Animals)

Abstract

Structural colors refer to colors generated by minuscule structures, with the characteristic dimension of the structures on the order of the wavelength of the visible light (i.e., some tens up to hundreds of nanometers). Examples for structural colors are the colors of CDs and DVDs, the colors of soap bubbles, or oil films on water (thin films), or the colors of certain butterfly wings (e.g., photonic crystals), and even plants. Tiny wax crystals in the blue spruce scatter the light (Tyndall scattering), resulting in the blue hue. Thin films in tropical understory plants and diffraction gratings in hibiscus and tulip flowers are just some more examples of the amazing variety of natural nanostructures that are the basis for coloration in some plants. This entry reviews the physics behind structural colors, lists plants, microorganisms, and virus species with nanostructures responsible for their coloration, and also touches upon the multifunctionality of materials in organisms, nanobioconvergence as an emergent science, and biomimetics as a promising field for knowledge transfer from biology to engineering and the arts. Introduction