Structural Color

The idea here is to mimic, and ultimately tune, the amazing optical properties of Morpho butterflies, whose nanostructured wings selectively reflect blue light with unfading metallic-like brilliance (impossible to achieve with pigments alone) and over a broad range of viewing angles, despite the nanostructures consisting only of transparent materials (chitin and air). Since the thin-film interference and single-slit diffraction effects that underlie the real butterfly’s intense blue color depend strongly on geometry, replacing the relatively stiff chitin with a viscoelastic polymer should enable altering the geometry, and hence tuning the coloration, of the ‘artificial butterfly’ by stretching the nanopatterned elastomer.