Full-Color Biomimetic Photonic Materials with Iridescent and Non-Iridescent Structural Colors

Abstract

The beautiful structural colors in bird feathers are some of the brightest colors in nature, and some of these colors are created by arrays of melanin granules that act as both structural colors and scattering absorbers. Inspired by the color of bird feathers, high-visibility structural colors have been created by altering four variables: size, blackness, refractive index, and arrangement of the nano-elements. To control these four variables, we developed a facile method for the preparation of biomimetic core-shell particles with melanin-like polydopamine (PDA) shell layers. The size of the core-shell particles was controlled by adjusting the core polystyrene (PSt) particles’ diameter and the PDA shell thicknesses. The blackness and refractive index of the colloidal particles could be adjusted by controlling the thickness of the PDA shell. The arrangement of the particles was controlled by adjusting the surface roughness of the core-shell particles. This method enabled the production of both iridescent and non-iridescent structural colors from only one component. This simple and novel process of using core-shell particles containing PDA shell layers can be used in basic research on structural colors in nature and their practical applications.

Color Engineering of Silicon Nitride Surfaces to Characterize the Polydopamine Refractive Index

“…The obtained values of real part of the refractive index are a 15 % smaller than the previously reported by Ming Xiao et al . and Ayaka Kawamura et al . (1.49 against 1.7).…”

“…Polydopamine has been essential in the progress of many diverse material areas due in part to its strong affinity for a great variety of surfaces together with its versatile chemistry which permits multiple functionalization approaches ,. It has been stated that polydopamine has a higher refractive index value than many synthetic polymers . Unfortunately, there is still controversy about the refractive index value ,,.…”

“…It has been stated that polydopamine has a higher refractive index value than many synthetic polymers . Unfortunately, there is still controversy about the refractive index value ,,. The reported values were mainly obtained for polydopamine colloidal dispersions ,.…”

Carbon Vesicles: A Symmetry‐Breaking Strategy for Wide‐Band and Solvent‐Processable Ultrablack Coating Materials

“…However, colloidal spheres usually exhibit structural colors due to the short‐range order of the composing spheres. [ 27–34 ] These colors (or absorption peaks) are rather unfavorable for developing ultrablack materials with wide absorbing band. Therefore, the rational design of hollow structures aimed to eliminate structural colors is of particular significance for the development of new solvent‐processable ultrablack materials.…”

Photonic Paints: Structural Pigments Combined with Water‐Based Polymeric Film‐Formers for Structurally Colored Coatings

“…In particular, colloidal assembly has been established as a simple but powerful bottom‐up approach to create the finely ordered nanostructures necessary for structural color . A full palette of intense, angle‐independent structural pigments can now be made from colloidal building blocks thanks to recent innovations, most notably on combinations of broadband optical absorbers with photonic pigments, and photonic glasses . Nevertheless, many photonic pigments are unsuitable for aqueous paint formulations: for example, those constructed from water‐dispersible colloids would not be likely to retain their nanostructure when dispersed in water .…”