Edge-on lamellar crystallization of oligo(3-methoxythiophene) in polyester matrix films and a gold tone development thereof

Abstract

A recently developed anion-doped 3-methoxythiophene oligomer was demonstrated to form edge-on lamellar crystallites in its drop-cast films. These films exhibit a stable gold-like lustrous color owing to the specific optical...

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.…”

Metallic Lustrous Porphyrin Foil with an Exceptional Refractive Index

“…Alternatively, the smooth surfaces of organic crystals and polymer films sometimes display strong noniridescent specular reflection and thus invoke a metallic luster. ,– Recently, Hoshino and coworkers established judicious manipulation of polythiophene films to faithfully imitate golden luster. – Noble metallic luster from crystals of alkylated mesogenic compounds, such as azobenzene and stilbene, is demonstrated by Kondo and coworkers. – In these cases, the metal-lustrous color mirrors the electronic structures of the organic compounds. Overlooking the theoretical establishment by Anex and Simpson in 1960, the noniridescent surface metallic reflection of organic materials had been phenomenologically reported until Kanbara and coworkers reported that the reflection spectrum of the smooth surface of the polymer film reliably agrees with the chromatic dispersion of the refractive index …”