Conducting polymers of octanoic acid 2-thiophen-3-yl-ethyl ester and their electrochromic properties

Octanoic acid 2-thiophen-3-yl-ethyl ester was synthesized via the reaction of 3-thiophene ethanol with octanoyl chloride. The resulting monomer was electrochemically homopolymerized in the presence of tetrabutylammonium tetrafluoroborate as the supporting electrolyte, in the acetonitrile/borontrifluoride ethyl ether solvent system. The resulting polymer was characterized using various experimental techniques. Spectroelectrochemistry analysis of the homopolymer reflects electronic transitions at 434, ≈800 and ≈1100 nm, revealing π–π* transition, polaron and bipolaron band formation, respectively, leading to esthetically pleasing color changes between transmissive yellow and blue, with reasonable switching times.