Bidispersed Colloidal Assemblies Containing Xanthommatin Produce Angle‐Independent Photonic Structures

Abstract The biological chromophore xanthommatin (Xa) contributes to the yellow, red, and brown colors and hues in cephalopods and arthropods. In many cases, Xa is also present as part of or coupled to supramolecular nanostructures, whose function has yet to be fully explored. To investigate how such structural elements impact the perceived color of these natural chromophores, amorphous photonic assemblies containing Xa chemically coupled to 100 nm polystyrene nanoparticles (PS100‐XA) are fabricated, and blended with pure polystyrene (PS) nanoparticles of varying sizes. Structural colors are observed comprising these bidispersed colloidal assemblies that are tuned by the particle size of PS nanoparticles, the concentration of PS100‐XA, the local environment, and the method of assembly. In all cases, the addition of PS100‐XA regulates the color hue and contrast of the resultant assemblies by increasing light absorption while minimizing incoherent light scattering. Taken together, the results demonstrate how biochromes like Xa can enhance the color intensity and the diversity in colors present in common photonic assemblies.