Development of Metal-Free Paints and Inks Producing a Metallic Luster

Abstract

Polythiophenes are multifunctional molecules and are considered as potential candidates for molecular electronics and imaging engineering. Among such polythiophenes, the author's group has found some derivatives that exhibit gold or bronze tones in their films formed by solution-casting or electropolymerization methods, and has conducted scientific and engineering investigations. In this review, the chemical synthesis of the thiophene derivatives and the physicochemical properties of their coating solution and cast films, as well as the electrochemical synthesis and the properties of the thiophene derivative films, are outlined. Through the series of the investigations described above, the mechanism is also discussed for the development of the gold-like luster. The thiophene derivatives prepared by chemical synthesis can be dissolved in some organic solvents and water, can be applied to various substrates such as glass plates and paper sheets, and show high stability in the air, making them good candidates for brilliant paints and inks.