Effect of polymerization rate on the chemical and optical properties of solution-cast metal-like lustrous films of water-soluble 3-methoxythiophene oligomer dyes

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

“…We note that differences in film thickness of about 1 to 3 μm did not affect the measurement of optical constants. The spectral shapes of n and κ for Films - 2 – 7 are similar to those for Film-1 and our previously reported Cl – -doped 3-methoxythiophene oligomers. − The n value increased sharply from approximately 500 to 600 nm and continued to increase moderately from approximately 700 nm. The κ value increased at a wavelength 50 nm shorter than n , reaching a maximum between 600 and 700 nm and gradually decreasing afterward.…”

“…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.…”

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

“…These colorimetric results are consistent with the results of the reection spectral measurements. In our previous studies, [17][18][19][20][21][22][23] we found that two types of crystallites are present in the solution-cast lms of O3MeOT, namely edge-on lamellar crystallites formed by the stacking of thiophene rings oriented perpendicular to the substrate (Fig. 4a), and face-on lamellar crystallites formed by the stacking of thiophene rings oriented parallel to the substrate (Fig.…”

“…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.…”