Synthesis and optical properties of azo-substituted polythiophene

The polythiophenes have been widely used as a conducting polymer and in many others applications such as electrochromism. The introduction of an azobenzene group can extend the possible applications to other fields, such as optical memories. In this work, a thiophenic monomer with an azobenzene moiety at the 3-position of the thiophene ring was synthesized by esterification reaction between the commercial dye disperse red 1 (DR1) and 3-thiopheneacetic acid. The UV-Vis spectra of polymer in solution were obtained and used to study the possible solvato- and thermochromic properties of the polymer. The thermochromic property was analyzed in the temperature interval of 10 to 70 °C. The solvents used in the solvatochromic study were hexane, chloroform, tetrahydrofuran, toluene, acetone, methanol, acetonitrile and dimethylformamide.