Development of Water-Based Paints with Gold and Bronze Tones Using High Molecular Weight Thiophene Oligomers

Abstract

To overcome various shortcomings associated with commercial metal-effect gloss paints containing metal flakes, the development of organic-based paints that exhibit metal-like colors has been eagerly awaited. Recently, one of the authors developed a potential candidate (ClO₄^－-doped oligo(3-methoxythiophene)) and its paint, but the required solvent was not industrially acceptable and the coating films displayed low glossiness. Very recently, we synthesized and characterized Cl^－-doped oligo(3-methoxythiophene) dyes that were water soluble and displayed a highly lustrous gold- and bronze-like hue upon curing, the outline of which is described. Specifically, we found that films derived from these oligomers form extremely regular and compact edge-on lamella crystallites through self-organization; these films also display a highly glossy metallic appearance due to the extremely high optical constants of the crystallites. These as-prepared films were easily soluble in water, but we also found that the films become insoluble in water upon dehydration, making industrial implementation feasible.