New electroactive and electrochromic aromatic polyamides with ether-linked bis(triphenylamine) units

Article abstract of DOI:10.1002/pola.27465

A new class of electroactive polyamides with etherlinked bis(triphenylamine) [O(TPA)₂] units were prepared through the direct phosphorylation polycondensation from N,N-di(4-aminophenyl)-N′,N′-diphenyl-4,4′-oxydianiline and aromatic dicarboxylic acids. These polyamides were amorphous with good solubility in many organic solvents, such as NMP and DMAc, and could be solution-cast into strong and flexible polymer films. Their decomposition temperatures (T_d) at a 10% weight-loss in nitrogen and air were recorded at 556-568°C and 537-555°C, respectively. The glass-transition temperatures (Tg) of all the polyamides were observed in the range of 218-253°C by DSC. Cyclic voltammograms of the polyamide films cast onto an indium-tin oxide (ITO)-coated glass substrate exhibited two reversible oxidation redox couples at 0.80-0.82 V and 0.96-0.98 V versus Ag/AgCl in an electrolyte containing acetonitrile solution. The polyamide films showed excellent electrochemical and electrochromic stability, with a color change from a colorless or pale yellowish neutral form to green and purple oxidized forms at applied potentials ranging from 0 to 1.2 V. These polymers can also be used to fabricate electrochromic devices, and they showed high coloration efficiency, high redox stability, and fast response time.