Stimuli-Responsive Biomimetic Metallic Luster Films Using Dye Absorption and Specular Reflection from Layered Microcrystals

Abstract

Inspired by the coloring mechanism of insects, we demonstrated the preparation of metallic luster materials by a combination of dye absorption and specular reflection from layered microcrystals. Metallic luster films were prepared by the recrystallization of diacetylene derivatives with different linker chains bearing azobenzene moieties. The lamellar structure of the molecules formed plate-like microcrystals, which were piled up to form layered films. A gold-like texture was observed due to the combination of the absorption of the azobenzene moiety and specular reflection from the surface of layered microcrystals. The film of the diacetylene derivative with a dodeca-5,7-diynedioate moiety used as a linker maintained its golden color regardless of light or thermal stimuli. In contrast, the color of the film composed of the diacetylene derivative containing the docosa-10,12-diynedioate linker turned purple due to solid-state polymerization by UV-light irradiation and maintained its metallic gloss. Additionally, the glossy color changed reversibly with changing temperature. The responsiveness of metallic luster films to stimuli was controlled by changing the linker chain length. The photo- and thermal-responsive metallic luster materials presented here can have a significant impact on decoration and ink applications.

Slippage- and load-induced changes in the crystalline orientation of oligo(3-methoxythiophene) powder to develop a gold-tone luster

“…1,2 Among these organic materials, the method by which the metallic luster is developed differs depending on the chemical properties of the material. Such methods include crystallization, [3][4][5][6][7][8] solidication by ltration, [9][10][11][12] electrochemical polymerization, [13][14][15][16] and solution application. [17][18][19][20][21][22][23] However, the design of a novel and more facile method for the development of metallic lusters could promote the application of the corresponding organic materials in the eld of decoration, while also expanding their range of uses.…”

Color Control of Metal-like Lustrous Films of 3-Alkoxythiophene Oligomer Dyes by Changing Subnanometer-Scale Interlamellar Distance

“…The different lengths of the alkoxy groups and the different DP p of the oligomers have almost no effect on the electronic state of each oligomer. In previously reported organic-based metallic luster materials, different luster colors resulted from changes in electronic states associated with major changes in the original molecular structure or external stimuli. − ,,,,− This is similar to the way the color of a substance can be modified. In contrast, our alkoxythiophene system has a consistent structure and electronic state and does not require external stimuli to generate distinct gloss colors.…”

“…Several molecules exhibit metallic luster solely with organic compounds. − For instance, polyacetylene, a semiconducting organic polymer, displays a silver luster, while air-stable fluorinated polyacetylene exhibits a gold luster in bulk solids . Kondo et al reported that low-molecular-weight azobenzene and stilbene derivatives exhibit gold- and silver-like luster, respectively, when crystallized and fabricated into films. ,, In addition, they reported luster color changes caused by external stimuli . Compounds that can exhibit metallic luster colors from organic materials alone are advantageous.…”

“…18,20,25 In addition, they reported luster color changes caused by external stimuli. 27 Compounds that can exhibit metallic luster colors from organic materials alone are advantageous. However, achieving different luster colors requires significant modifications in the original molecular structure or an external stimulus, similar to changing the color of a substance.…”

A Layered Polydiacetylene Containing Hydrogen‐Bonding 4,4′‐Bipyridyl Guests: Reversible Color Changes with a Wide‐Range Temperature Response

“…[12][13][14][15] The color, responsivity, and reversibility are tuned by the molecular design and synthesis. [16][17][18][19][20][21][22][23] However, it is not easy to control the colorchange properties systematically. In particular, expansion of the controllable range is not easily achieved by the molecular design.…”