A novel aromatic diamide-diamine monomer, 4,4′-di(3-aminobenzamido)-4″-(N-carbazolyl)triphenylamine, was successfully synthesized and subsequently polymerized with five aromatic tetracarboxylic acid dianhydrides (PMDA, BPDA, OPDA, 6FDA, and DSDA) to produce a series of electroactive poly(amide-imide)s (PAIs). The chemical structures of the diamine monomer and its derived PAIs are confirmed through FT-IR, 1H NMR, and H–H COSY NMR spectroscopy. The thermal properties of the polymers are evaluated using DSC and TGA. Experimental results indicate that the glass transition temperatures of these PAIs range from 286 to 303 °C, with a 10% weight loss temperature exceeding 484 °C in both air and nitrogen atmospheres. Moreover, the carbon residue rate at 800 °C in nitrogen exceeds 50%, demonstrating excellent thermal stability. The polymers are soluble in polar organic solvents, and smooth and highly adherent films can be coated onto ITO glass substrates. The cyclic voltammograms of these films exhibit a two-stage redox characteristic, with significant absorption behavior observed in the visible and near-infrared regions during oxidation. The film color transitions from colorless in the neutral state to green and blue in the oxidized states, displaying stable electrochromic behavior in the first stage. Further verification of their optoelectronic performance and electrochromic stability is achieved through multiple on-off switching cycling tests, indicating that the PAIs hold potential for applications in smart optoelectronic devices and electrochromic films.
Hung et al. (Fri,) studied this question.