Full‐Spectrum Photonic Pigments with Non‐iridescent Structural Colors through Colloidal Assembly

Park, Jin Gyu; Kim, Shin‐Hyun; Magkiriadou, Sofia; Choi, Tae Min; Kim, Young-Seok; Manoharan, Vinothan N.

doi:10.1002/anie.201309306

Cited by 222 publications

(202 citation statements)

References 38 publications

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“…3,5 Similarly, disorder introduced into CBPM can lead to angle-independent structural colors. [180][181][182][183][184][185] An example of such angle independence can be seen in Figure 8C. It should be noted that there is a blue tinge to the colors that can be produced using this method.…”

Section: Factors Affecting Optical Applicationsmentioning

confidence: 89%

A colloidoscope of colloid-based porous materials and their uses

et al. 2016

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Nature evolved a variety of hierarchical structures that produce sophisticated functions. Inspired by these natural materials, colloidal self-assembly provides a convenient way to produce structures from simple building blocks with a variety of complex functions beyond those found in nature. In particular, colloid-based porous materials (CBPM) can be made from a wide variety of materials. The internal structure of CBPM also has several key attributes, namely porosity on a sub-micrometer length scale, interconnectivity of these pores, and a controllable degree of order. The combination of structure and composition allow CBPM to attain properties important for modern applications such as photonic inks, colorimetric sensors, self-cleaning surfaces, water purification systems, or batteries. This review summarizes recent developments in the field of CBPM, including principles for their design, fabrication, and applications, with a particular focus on structural features and materials' properties that enable these applications. We begin with a short introduction to the wide variety of patterns that can be generated by colloidal self-assembly and templating processes. We then discuss different applications of such structures, focusing on optics, wetting, sensing, catalysis, and electrodes. Different fields of applications require different properties, yet the modularity of the assembly process of CBPM provides a high degree of tunability and tailorability in composition and structure. We examine the significance of properties such as structure, composition, and degree of order on the materials' functions and use, as well as trends in and future directions for the development of CBPM.

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Section: Factors Affecting Optical Applicationsmentioning

confidence: 89%

A colloidoscope of colloid-based porous materials and their uses

et al. 2016

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“…9 These double-emulsion drops can be further compressed by imposing osmotic pressure, allowing for post-fabrication control of the structural colors. 10, 11 Various types of particles can be used: charged nanoparticles tend to form highly ordered crystalline arrays whose color can be adjusted by osmotic pressure, 10 whereas soft hydrogel nanoparticles naturally pack into dense amorphous structures that show noniridescent color that can be tuned in a similar manner. 11 However, the relationship between the internal nanostructure of the microcapsules and the strength and rate of compression is still not understood.…”

Section: ■ Introductionmentioning

confidence: 99%

Osmotic-Pressure-Mediated Control of Structural Colors of Photonic Capsules

et al. 2015

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Crystalline or glassy materials made of colloidal nanoparticles show distinctive photonic effects; the crystals exhibit sparkling colors with strong iridescence, while the glasses show noniridescent colors. Both colors are the results of constructive interference of the reflected light by the nonadsorbing nanostructures. Such colored materials have potential applications as nonfading colorants in reflective color displays, optical sensors, coatings, and cosmetics. All of these applications require granular format of the nanostructures; however, precise control of the nanostructures from amorphous to crystalline over the submillimeter length scale remains challenging. Here, we present micrometer-level control of photonic nanostructures confined in microcapsules through osmotic-pressure-mediated concentration. We encapsulate aqueous suspensions of colloidal particles using double-emulsion drops with ultrathin layers of photocurable resin. The microcapsules are then isotropically compressed by imposing a positive osmotic pressure difference that forces the water out through the thin resin membrane. We find that the internal nanostructure of our photonic microcapsules can be kinetically controlled from crystalline to amorphous; slow concentration in small pressure gradients yields colloidal crystals with sparkling color patterns, whereas fast concentration in large pressure gradients yields glassy packing with only short-range order, which show uniform color with little iridescence. By polymerizing the thin monomeric shell, we permanently fix these nanostructures. Our findings provide new insights into the design and synthesis of optical materials with controlled structural colors. ■ INTRODUCTIONPeriodic colloidal nanostructures on the scale of half the wavelength of visual light show reflected colors, because of the constructive interference of selected wavelengths of light. 1 Such structural colors are distinguished from the usual "chemical colors" that arise from absorption spectra. When the colloidal nanostructures have long-range order, the color is iridescent; 2 when the order is short-ranged, the color is noniridescent and isotropic. 3 Although most chemical colors eventually fade, because of the oxidation or reaction of their chemical structures, structural colors can persist for as long as their periodic structures survive. Moreover, the structural colors can be dynamically tuned by controlling the periodicity of the nanostructures through chemical environment, temperature, and electric fields. 4 These unique properties of structural colors make them appealing for many applications, including colorimetric sensors, pigments, and reflection-mode displays. 4,5 Structurally colored pigments have been produced using emulsion drops to confine colloidal assembly; 6−11 the resulting pigments can be assembled to build photonic devices or can be dispersed in liquid media to make paints. Single-emulsion drops yield consolidated granules of colloidal crystals through solvent evaporation, 7 and double-emulsion drops en...

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“…The pore periodicity of inverse opals is well-known to affect the propagation of electromagnetic radiation in optical films [2] and has also been utilized for electrochemical applications [4]. Additionally, disordered structures have been considered for random lasing and resonance-dependent Anderson localization [5,6], as well as for omnidirectional reflectors, TBCs [7], and structural coloration [8,9] due to their strong scattering of light.…”

Section: Introductionmentioning

confidence: 99%