Synthesis and characterization of novel electrochromic poly(amide-imide)s with N,N′-di(4-methoxyphenyl)-N,N′-diphenyl-p-phenylenediamine units

• Published in: RSC advances 2015, Vol.5 (113), p.93591-93606
• Main Authors: Hsiao, Sheng-Huei, Teng, Chia-Yin, Kung, Yu-Ruei
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C5RA17520H

We developed a new efficient procedure for the synthesis of a bistriphenylamine diamine monomer, N , N ′-bis(4-aminophenyl)- N , N ′-bis(4-methoxyphenyl)-1,4-phenylenediamine ( 3 ). A new dicarboxylic acid monomer bearing two built-in imide rings, namely N , N ′-bis(trimellitimidophenyl)- N , N ′-bis(4-methoxyphenyl)-1,4-phenylenediamine ( 4 ), was synthesized from the condensation of diamine 3 with two equivalent amounts of trimellitic anhydride. Several novel electroactive poly(amide-imide)s (PAIs) containing N , N ′-di(4-methoxyphenyl)- N , N ′-diphenyl- p -phenylenediamine [TPPA(OMe) 2 ] units have been prepared by the phosphorylation polyamidation reactions from diamine 3 with four imide ring-preformed dicarboxylic acids or from diimide-diacid 4 with 4,4′-oxydianiline and diamine 3 , respectively. All the PAIs were readily soluble in many organic solvents and could be solution-cast into tough and flexible polymer films. These PAIs exhibited glass-transition temperatures ( T g s) in the range 206–292 °C, and most of them did not show significant weight-loss before 450 °C. The PAI films revealed reversible electrochemical oxidation processes accompanied with strong color changes from the pale yellow neutral state to yellowish green and deep blue oxidized. Incorporating the TPPA(OMe) 2 unit on the amide side of PAIs led to lower oxidation potentials and higher redox and electrochromic stability.