3D 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.

Printing Crack‐Free Microporous Structures by Combining Additive Manufacturing with Colloidal Assembly

“…[4] For instance, high-power electronics in aerospace vehicles become continuously smaller, run longer cycles, and require higher power, which must eventually be compensated with more sophisticated heat management were polycrystalline and exhibited iridescent structural coloration. To print geometries with non-iridescent, angular independent structural coloration, others [11,13] continued the approach by adding a viscous polymer phase to the suspension. Thereby, ordering of the colloids is impeded, which forms an amorphous particle assembly, i.e., a photonic glass (PhG) structure.…”

“…This printing approach and similar ones exploiting inkjet printing [ 10 ] have gained more and more attention in recent years. [ 11–15 ] Initially, Tan et al [ 14 ] printed free‐standing columns via direct writing made from submicron‐sized, monodisperse polystyrene , gold or silica particles. The obtained columns were polycrystalline and exhibited iridescent structural coloration.…”

“…The obtained columns were polycrystalline and exhibited iridescent structural coloration. To print geometries with non‐iridescent, angular independent structural coloration, others [ 11,13 ] continued the approach by adding a viscous polymer phase to the suspension. Thereby, ordering of the colloids is impeded, which forms an amorphous particle assembly, i.e., a photonic glass (PhG) structure.…”

“…Thereby, ordering of the colloids is impeded, which forms an amorphous particle assembly, i.e., a photonic glass (PhG) structure. [ 11,13 ] The presence of a polymeric phase; however, limits the functionality and applicability of the obtained colloidal structures to that of the polymeric phase, e.g. low‐temperature stability, low‐chemical resistance, as well as low strength and stiffness.…”

“…This printing approach and similar ones exploiting inkjet printing [10] have gained more and more attention in recent years. [11][12][13][14][15] Initially, Tan et al [14] printed free-standing columns via direct writing made from submicron-sized, monodisperse polystyrene , gold or silica particles. The obtained columns To date high printing resolution and scalability, i.e., macroscale component dimensions and fast printing, are incompatible characteristics for additive manufacturing (AM) processes.…”