Effect of polymerization conditions on physicochemical properties of gold-like lustrous films of organic solvent soluble 3-methoxythiophene oligomers

Abstract

Solution-cast films of ClO4−-doped oligo(3-methoxythiophene) exhibit a luster similar to that of metallic gold; however, the effects of synthetic conditions on the physicochemical properties of the above oligomer and its films remain underexplored. To bridge this gap, this study examines how these properties are affected by (i) the time required to add the oxidant solution to the monomer solution (ta) and (ii) the polymerization time (tp) for oligomer synthesis, revealing that oligomer molecular weight, film conductivity, and the amount of edge-on lamellar crystallites increase with decreasing ta and/or increasing tp. Given that the crystallinity of edge-on lamellar structures, together with film surface roughness, strongly influences film specular reflectance, the obtained results are expected to facilitate the fabrication of conductive oligo(3-methoxythiophene) films with tunable color and metal-like luster for diverse applications. The oxidant addition time and polymerization time were varied during the synthesis of oligo(3-methoxythiophene), and the effect of such polymerization conditions on the physicochemical properties of the oligomer and its cast films was investigated. The polymerization conditions changed the oligomer molecular weight and the amount of edge-on lamellar crystallites in the films and, in turn, affected the color and gloss of the films. The obtained results are expected to facilitate the fabrication of conductive oligo(3-methoxythiophene) films with tunable color and metal-like luster for diverse applications.