Azomethine coupled fluorene-thiophene-pyrrole based copolymers: Electrochromic applications

Two new copolymers were synthesized via the electrochemical copolymerization of 4,4′-(9H-fluorene-9,9-diyl)bis(N-(thiophen-2-ylmethylene)aniline) (FTMA) with thiophene (Th) and pyrrole (Py). According to the X-ray Photoelectron Spectroscopy (XPS) measurements, the polymers FTMA-co-Th and FTMA-co-Py possessed monomer ratios of nearly 1/5 (FTMA/Th) and 1/2 (FTMA/Py). Spectroelectrochemical investigations showed that FTMA-co-Th was a red color at low potentials and a blue color at high potentials. FTMA-co-Py was purple at low potentials and dark gray at high potentials. Spectroelectrochemical monitoring showed good absorption recoveries over repeated potential scans. As a result, FTMA-co-Th and FTMA-co-Py may be good candidates for electrochromic devices (ECDs) and could be used as coloring agents in electrochromic layers in ECDs.