Effect of π–π interaction-induced secondary doping on the gold-like luster of oligo(3-methoxythiophene) cast films

Oligo(3-methoxythiophene)s as Water-Soluble Dyes for Highly Lustrous Gold- and Bronze-like Metal-Effect Coatings and Printings

“…The XRD pattern contained signals at 2θ = 7.41°, ∼15° (shoulder), and 26.2° (see Figure a). The former two signals correspond to reflections from the (100) and (200) planes of the edge-on lamella (Figure e), formed by the thiophene ring being oriented perpendicular to the plate; the latter peak corresponds to reflection from the face-on lamella (020) plane, as shown in Figure f. − The interlayer distances that corresponded to 2θ = 7.41° and 26.2° are a = 1.19 and b = 0.34 nm, respectively. These values are similar to those obtained from the XRD pattern of as-synthesized oligomer 1 powder ( a = 1.18 and b = 0.34 nm).…”

“…Recently, it was shown that a ClO 4 – -doped 3-methoxythiophene oligomer produced gold-like lustrous films while satisfying all of the aforementioned desiderata. 24 − 26 This oligomer is possibly the first nonmetallic material that is likely to be used during the industrial production of lustrous inks and paintings. However, the oligomer was solvated in either nitromethane or acetonitrile that are considered to be employee-unsafe.…”

“… 29 − 31 The aforementioned 3-methoxythiophene oligomer also forms self-organizing lamellar crystal structures similar to those of poly(3-alkylthiophene), which have been studied extensively. 24 − 26 However, this oligomer displays specific properties arising from compactness of the methoxy group, high levels of electron donation, and multiple supramolecular interaction points; the oligomer shows specific morphological, optical, and chemical properties different from those of poly(3-alkylthiophene). For example, the former has larger optical constants (refractive index and extinction coefficient) than the latter.…”

“…To date, poly­(3-alkylthiophene) molecules, with an alkyl group bound to the 3-position of the thiophene ring, have displayed self-organizing properties, capable of forming lamellar crystal structures, attributed to intermolecular interactions. This unique self-orientating property is promising for use in applied organic electronics devices. − The aforementioned 3-methoxythiophene oligomer also forms self-organizing lamellar crystal structures similar to those of poly­(3-alkylthiophene), which have been studied extensively. − However, this oligomer displays specific properties arising from compactness of the methoxy group, high levels of electron donation, and multiple supramolecular interaction points; the oligomer shows specific morphological, optical, and chemical properties different from those of poly­(3-alkylthiophene). For example, the former has larger optical constants (refractive index and extinction coefficient) than the latter. , …”

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

“…For the formation of pure O3MeOT films so far, nitromethane and acetonitrile were used as coating solvents. 14,16,17 The film produced with nitromethane (boiling point, T b = 374 K) exhibited a gold-like luster and mirroring surface when dried in air for B10 min after drop-casting, while the film produced using acetonitrile (T b = 355 K) had a dull brown luster after several minutes of drying. However, rubbing of the acetonitrile film surface transformed the appearance to a gold-like luster.…”