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

Abstract

Rubbing and pressing of blackish-brown 3-methoxythiophene powder produced layers and tablets with gold tone luster, respectively, due to increased edge-on lamellar crystallites.

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

“…The XRD patterns of these films exhibited peaks at 2θ = 5–8°, approximately 15, and 25°. In previous studies, we attributed the first and second peaks to reflections from the crystallographic (100) and (200) planes, respectively, confirming the lamellar structure of the films. − The peak at 2θ ≈ 25° corresponds to the (020) plane associated with the π–π stacking of the oligomer chains. The XRD analyses were performed in the out-of-plane mode.…”

“…Based on our previous studies, we can conclude that the glossy appearance of Film-1 is due to the compact lamellar crystallites formed by the 3-methoxythiophene oligomer chains in the film. − These crystallites exhibited very large optical constants, as shown in Figure . Although the specular refraction spectra of Film-1 and the vacuum-deposited gold film appear similar, the n and κ characteristics and mechanisms that produce the reflections differ.…”

“…We previously demonstrated a coating film of an anion-doped 3-methoxythiophene oligomer, synthesized by chemical oxidative polymerization, exhibiting a gold luster. − We also found that the metallic luster of this film does not originate from structural color or free electrons . Instead, it has been demonstrated that light is reflected due to the large optical constants (reflective index and extinction coefficient) caused by edge-on lamellar crystals formed by the perpendicular orientation of the thiophene rings to the substrate in the coating film.…”

Molecular Design of Pyrene and Its Derivatives to Make Microcrystalline Films with Silver Luster Effect Using Drop-Casting Method

“…This effect, as well as the added metals themselves, causes environmental pollution. − In order to solve these problems, metallic-appearing luster materials are being developed using organic compounds that do not contain any metal. Previous works have reported such materials derived from various organic compounds, including thiophene, − pyrrole, − aniline, porphyrin, thiadiazole, stilbene, azobenzene, − and diarylethene derivatives . Although many organic metallic-appearing luster materials have been developed, only stilbene derivatives have been reported for silver luster.…”