Yu-Ruei Kung

Novel near-infrared and multi-colored electrochromic polybenzoxazines with electroactive triarylamine moieties

Two triarylamine-containing flexible polybenzoxazine films with Tg up to 312 °C were prepared by the thermally induced curing reaction of the corresponding polybenzoxazine precursors, which were synthesized by the reaction of paraformaldehyde with bisphenol A and 4,4′-diamino-4′′-methoxytriphenylamine (1) or N,N′-bis(4-aminophenyl)-N,N′-di(4-methoxyphenyl)-1,4-phenylenediamine (2). By introduction of triarylamine units into the polybenzoxazine precursors, the resulting solution-processable polybenzoxazine precursor films not only exhibited interesting multi-colored electrochromic behavior with a high contrast ratio both in the visible range and near infrared region (NIR) but also could effectively increase the oxidation stages when compared with their corresponding polyamides.

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

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 (Tgs) 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.