Manufacturing Large-scale Materials with Structural Color

Abstract

Living organisms frequently use structural color for coloration as an alternative mechanism to chemical pigmentation. Recently there has been a growing interest to translate structural color into synthetic materials as a more durable and less hazardous alternative to conventional pigments. Efforts to fabricate structurally colored materials take place in different fronts, from 3D printing to spray-coating and roll-to-roll casting. Stability, performance, and quality of the color, the environmental impact of the materials or their manufacturing methods are some of the heavily researched topics we discuss. First, we highlight recent examples of large-scale manufacturing technologies to fabricate structurally colored objects. Second, we discuss the current challenges to be tackled to create perfect appearances which aim at the full color gamut while caring for environmental concerns. Finally, we discuss possible scenarios that could be followed in order to involve other manufacturing methods for creating structurally colored objects.

Wrinkle nanostructures generate a novel form of blue structural color in great argus flight feathers

“…Given the recent interest in biomimetic design of structurally colored surfaces and materials 27 , 28 , 29 and the novel wrinkle structure we describe here, we anticipate the results of this study will continue to inspire the engineering design of non-iridescent color-producing structures based on wrinkling mechanisms. This is especially relevant given the growing interest in applying structural color to manufactured objects, 30 which is facilitated by methods involving only surface modifications.…”

“…These shared features of surface keratin nanostructures among archosaurs ( Figure 3 ) hint at a possible homology of their underlying developmental mechanisms. While wrinkle structures are widely found in living organisms, 32 , 33 and are actively under consideration for biomimetic applications, 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 this is the first example of a biophotonic (i.e., color-producing) wrinkle nanostructure in birds.…”

Poly(4-vinylpyridine) and Poly(methacrylic acid) Particle Architectures for pH-Responsive and Mechanochromic Opal Films

“…While nature has mastered the construction of nanostructures with well-defined macroscopic effects and purposes, as of today, the industrial production of structurally colored materials is rare. ,,, One of the most promising building blocks for synthetically derived structural colors are core–shell particles (CSP), due to their inherent ability to self-assemble into highly ordered photonic crystal structures . Further advantages of CSP are the easily tailorable and scalable synthesis, high variety of processing options, and their tunable thermal, rheological and mechanical properties. − Moreover, color quality does not suffer from internal multiple scattering or interference by individual particles. , …”

“…Thereby synthesized polymer-based CSP often consist of a cross-linked polystyrene core and polyalkyl acrylate shell. After synthesis, various self-assembly techniques can be applied, as reviewed by different authors. ,,,, One of the most promising processing techniques for CSP is melt-shear organization: the polymer is placed between the plates of a laboratory or industrial press. At moderate temperatures, the comparably soft shell-polymer forms a continuous and viscous matrix around the hard cores.…”

“…Typical issues are the need for a binder, a solvent, and/or a substrate, the difficult or nonexisting process scalability, or the introduction of a significant number of lattice defects during processing, which leads to a deterioration of color quality. Moreover, subsequent processing steps, such as drying, can lead to the formation of voids or cracks. , None of these disadvantages, however, apply to opal films produced with the above-described melt-shear organization technique . The combination of established pH-responsive polymers with a hard core–soft shell particle architecture, which is suitable for melt-shearing, may thus pave the way for a novel and promising types of multistimuli-responsive structural color materials.…”