Three-dimensional printing of photonic colloidal glasses into objects with isotropic structural color

Abstract

Structural color is frequently exploited by living organisms for biological functions and has also been translated into synthetic materials as a more durable and less hazardous alternative to conventional pigments. Additive manufacturing approaches were recently exploited for the fabrication of exquisite photonic objects, but the angle-dependence observed limits a broader application of structural color in synthetic systems. Here, we propose a manufacturing platform for the 3D printing of complex-shaped objects that display isotropic structural color generated from photonic colloidal glasses. Structurally colored objects are printed from aqueous colloidal inks containing monodisperse silica particles, carbon black, and a gel-forming copolymer. Rheology and Small-Angle-X-Ray-Scattering measurements are performed to identify the processing conditions leading to printed objects with tunable structural colors. Multimaterial printing is eventually used to create complex-shaped objects with multiple structural colors using silica and carbon as abundant and sustainable building blocks.

Photonic Lignin with Tunable and Stimuli-Responsive Structural Color

“…The structural color of a colloidal crystal mainly originates from the Bragg reflection at visible light, while the structural color of a colloidal amorphous array is more complicated and depends on diverse scattering effects such as Mie resonances. 30,31 Many meaningful research works demonstrate that the selective reflection of a colloidal amorphous array is the function of the diameter and reflective index of colloidal particles. 26,29,30,33,34 The reflected wavelength center can be roughly described by eqs 1 and 2:…”

“…30,31 Many meaningful research works demonstrate that the selective reflection of a colloidal amorphous array is the function of the diameter and reflective index of colloidal particles. 26,29,30,33,34 The reflected wavelength center can be roughly described by eqs 1 and 2:…”

“…The photonic lignin was composed of monodisperse LCSs which were arranged into an array with short-range order. Such kind of array is also known as a colloidal amorphous array, , amorphous photonic crystal, colloidal glass, , or photonic glass. , The structural color of the colloidal amorphous array is different from the long-range ordered colloidal crystal. The structural color of a colloidal crystal mainly originates from the Bragg reflection at visible light, while the structural color of a colloidal amorphous array is more complicated and depends on diverse scattering effects such as Mie resonances. , Many meaningful research works demonstrate that the selective reflection of a colloidal amorphous array is the function of the diameter and reflective index of colloidal particles. ,,,, The reflected wavelength center can be roughly described by eqs and : λ max ∝ d n eff n eff = normalΦ n 1 2 + ( 1 − Φ ) n 2 2 where λ max represents the wavelength of reflection peak, d represents the average diameter of colloidal particle, n eff represents the effective refractive index, n 1 and n 2 represent the refractive index of colloidal particle and media, respectively, and Φ represents the volume fraction of colloidal particle in the colloidal array.…”

“…The photonic lignin was composed of monodisperse LCSs which were arranged into an array with short-range order. Such kind of array is also known as a colloidal amorphous array, 26,27 amorphous photonic crystal, 28 colloidal glass, 29,30 or photonic glass. 31,32 The structural color of the colloidal amorphous array is different from the long-range ordered colloidal crystal.…”

Manufacturing Large-scale Materials with Structural Color

“…Recently 3D printing of colloidal particles with isotropic coloration was successful. [34] Here researchers have shown that silica particles mixed with a co-polymer and carbon black can be optimized to have the right consistency to prepare an ink for extrusion. [34] Such an ink can be extruded from a nozzle to obtain complex geometries.…”