Quasiordered photonic band gap materials of biologic origin: butterfly scales

Individual, unsupported scales of two male butterflies with dorsal blue and ventral green color were compared by microscpectrometric measurements, optical and electronic microscopy. All the scales are colored by photonic band gap type materials built of chitin (n = 1.58) and air. The different scales are characterized by different degrees of order from fully ordered single crystalline blue scales of the Cyanophrys remus butterfly through polycrystalline green scales on the ventral side of the same butterfly, to the most disordered dorsal blue scales of the Albulina metallica, where only the distance of the first neighbors is constant. The different scale nanoarchitectures and their properties are compared.