Effect of the Polydopamine Composite Method on Structural Coloration: Comparison of Binary and Unary Assembly of Colloidal Particles

Abstract

Melanin influences light reflection and absorption and is known to be one of the elements producing structural color, such as that in the feathers of birds. In this study, we used polydopamine (PDA), an artificial melanin, as a light-absorbing material and examined in detail the effect of its composite method on the structural color. The following two composite methods were investigated using cerium­(IV) oxide (CeO2) particles as a core particle: binary coassembly of CeO2 and PDA particles and unary assembly of CeO2@PDA core–shell particles. Although both methods dramatically improved the visibility of the structural color by suppressing the scattered light owing to the light absorption capability of the PDA, there was a difference in the particle arrangement, angle dependence of the structural color, and color tone change. By selecting the PDA composite method, the guidelines for providing high visibility and the desired structural color were presented.

Self-assembly of colloidal particles into amorphous photonic crystals

“…The structure of APCs can be created by controlling the coefficient of variation (CV) of colloidal particle diameters. 41,149,150 For example, Kohri et al…”

Control of Structural Coloration by Natural Sunlight Irradiation on a Melanin Precursor Polymer Inspired by Skin Tanning

“…Finally, a comparison was made between the obtained pellets and the CeO 2 @PDA particle pellets, which has been reported to exhibit vivid structural colors. 37 To compare the absorbance ability of PDA, the CeO 2 @PDA core−shell particles with approximately the same shell thickness (7 nm) as that of the CeO 2 @PTy core−shell particles were prepared. The color of the pellet samples obtained can be seen in the International Commission on Illumination (CIE) 1931 chromaticity diagram (Figure 8).…”

“…CeO 2 @PDA core−shell particles were prepared according to the procedure in a previously published study. 37 Measurements. Scanning electron microscopy (SEM) micrographs of the samples were obtained using a scanning electron microscope (JSM-6510A and JSM-7800F; JEOL).…”

“…CeO 2 particles coated with polyvinyl pyrrolidone (PVP) were provided by Hokko Chemical Industry Co., Ltd. (Tokyo, Japan). CeO 2 @PDA core–shell particles were prepared according to the procedure in a previously published study …”

Polymer Nanoparticle-Based Spherical Photonic Pigments for Dye-Free Noniridescent Bright Coloring

“…PD can be easily obtained by oxidative polymerization of dopamine in basic aqueous medium, either to coat different substrates or in the form of nanoparticles with uniform size and shape. Taking inspiration in the colored feathers of many birds, − PD has been studied as a building block to obtain photonic materials. − However, the use of PD to both introduce disorder in the structure of spherical colloidal photonic pigments and reduce the contribution of diffuse light scattering has not been explored.…”