Structural Coloration with Nonclose‐Packed Array of Bidisperse Colloidal Particles

Abstract

Colloidal crystals and glasses have their own photonic effects. Colloidal crystals show high reflectivity at narrowband, whereas colloidal glasses show low reflectivity at broadband. To compromise the opposite optical properties, a simple means is suggested to control the colloidal arrangement between crystal and glass by employing two different sizes of silica particles with repulsive interparticle potential. Monodisperse silica particles with repulsive potential spontaneously form crystalline structure at volume fraction far below 0.74. When two different sizes of silica particles coexist, the arrangement of silica particles is significantly influenced by two parameters: size contrast and mixing ratio. When the size contrast is small, a long‐range order is partially conserved in the entire mixing ratio, resulting in a pronounced reflectance peak and brilliant structural color. When the size contrast is large, the long‐range order is rapidly reduced along with mixing ratio. Nevertheless, a short‐range order survives, which causes low reflectivity at a broad wavelength, developing faint structural colors. These findings offer an insight into controlling the colloidal arrangements and provide a simple way to tune the optical property of colloidal arrays for structural coloration.

Self-assembly of colloidal particles into amorphous photonic crystals

“…7a). 147 At a two particle size contrast of 0.13, the long-range ordered bi-disperse array exhibited high reflectivity and narrow reflection peaks. A short-range ordered structure was established when the size contrast was increased to 0.23 (Fig.…”

“…APCs were prepared easily and rapidly by bi-disperse-suspension assembly, and the transformation from PCs to APCs structure could be achieved by adjusting the size contrast of binary particles. 147,153 However, it is necessary to alter the size of binary particles and the ratio of each component when adjusting the structural color, which is a tedious process. 153 Copyright 2019, American Chemical Society.…”

“…180 Kim et al prepared mechanically discolored APC elastomers by studying the assembly of bi-dispersed colloidal particles in PEGPEA resin. 147,153 Some of the APC elastomers with self-healing properties will be fully utilized in colorimetric sensors. 29,180,181 Takeoka et al prepared APCs by assembling soft particles with temperature-sensitive shell which caused reversible changes of reflection peaks with temperature.…”

Bioinspired structural color nanocomposites with healable capability

“…Structural color nanocomposites can be obtained by the combination of ordered nanostructures with polymeric materials, and conventionally, they can be usually obtained by (1) assembly of colloidal particles, followed by the infiltration of a polymerizable precursor and solidification process, 13,44,[62][63][64] or (2) assembly of colloidal particles in the presence of the monomers, followed by a polymerization process. 22,48,[65][66][67] Due to the facile and cost-effective preparation, a wide range of colloidal particles, such as silica NPs (SiO 2 NPs), polystyrene NPs (PS NPs), Fe 3 O 4 NPs, and others, are usually chosen as building blocks for the construction of photonic structures with an opal structure by the assembly strategy. 16 Besides, the structural color nanocomposites can also be obtained by replicating the assembled opal structures, which is known as the inverse opal structure, by a series of preparation steps, such as fabrication of the template, infusion of the polymerizable monomer, followed by polymerization of the monomer, and removal of the colloidal template.…”

Synthesis, microscopy and manipulation of colloidal matter

“…With this detailed study, the method became well established and is often referred to in literature as the 'two phase method' 4 . Particles made in this way have since been frequently applied in the assembly of photonic crystals [30][31][32][33][34][35][36][37] and the fluorescently dyed particles have found application in biological mapping [38].…”