Redox-Stable and Multicolor Electrochromic Polyamides with Four Triarylamine Cores in the Repeating Unit

Two new triarylamine-based diamine monomers, namely, N,N'-bis(4-methoxyphenyl)-N,N'-bis(4-(4-aminophenyl-4'-methoxyphenylamino)phenyl)-p-phenylenediamine (3) and N,N'-bis(4-methoxyphenyl)-N,N'-bis(4-((4-aminophenyl-1-naphthyl)amino)phenyl)-p-phenylenediamine (7), were successfully synthesized and led to two series of electroactive polyamides by polycondensation reactions with common aromatic dicarboxylic acids. The polymers demonstrated multicolored electrochromism, high optical contrast, and remarkable enhancements in redox and electrochromic stability. Compared to other triarylamine-based polymers, the studied polyamides exhibited enhanced electrochromic stability (only 3~6% decay of its coloration efficiency at 445 nm after 14,000 switching cycles) at the first oxidation stage. The polyamides also showed strong absorption in the near-infrared region upon oxidation. Polymers with multicolored electrochromism and high redox stability can be developed by incorporation of four triarylamine cores in each repeat unit and electron-donating methoxy groups on the active sites of the triphenylamine units.