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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.

A new electroactive monomer with two 2,5-di(2-thienyl)pyrrole (SNS) units and one diphenylpyrenylamine (DPPA) subunit, namely N,N-bis(4-(2,5-di(2-thienyl)-1H-pyrrol-1-yl)-phenyl)-1-aminopyrene (DPPA-2SNS), was synthesized from 1,4-di-(2-thienyl)butane-1,4-dione with N,N-di(4-aminophenyl)-1-aminopyrene through the Paal–Knorr condensation reaction. Visible and near-infrared (NIR) electrochromic polymer films could be facilely generated on the ITO-glass surface by the electrochemical polymerization of DPPA-2SNS in an electrolyte solution. The electro-synthesized polymer films exhibit multi-staged redox processes and multi-colored anodic electrochromic behavior. A multi-colored electrochromism, with yellowish orange, greyish blue, and purplish black colors, was observed in the polymer film by applying a positive potential. The polymer films exhibit reasonable coloration efficiency, fast response time, and good cycling stability, especially when switched between neutral and the first oxidation states. For comparison, N-(1-pyrenyl)-2,5-di(2-thienyl)pyrrole (Py-SNS) was also prepared and characterized with electrochemical and electro-optical properties.

Two electropolymerizable monomers with a methoxytriphenylamine core linked via amide groups to two triphenylamine (TPA) or N-phenylcarbazole (NPC) terminal groups, namely 4,4′-bis(4-diphenylaminobenzamido)-4′′-methoxytriphenylamine (MeOTPA-(TPA)2) and 4,4′-bis(4-(carbazol-9-yl)benzamido)-4′′-methoxytriphenylamine (MeOTPA-(NPC)2), were synthesized and characterized by FTIR and 1H NMR spectroscopy, mass spectrometry, and cyclic voltammetry. The electrochemical polymerization reactions of these MeOTPA-cored monomers over indium tin oxide (ITO) electrode allow the generation of electroactive poly(amide-amine) films. The electro-generated polymer films exhibited reversible redox processes and multi-colored electrochromic behaviors upon electro-oxidation, together with moderate coloration efficiency and cycling stability. The optical density changes (ΔOD) were observed in the range of 0.18–0.68 at specific absorption maxima, with the calculated coloration efficiencies of 42–123 cm2/C. Single-layer electrochromic devices using the electrodeposited polymer films as active layers were fabricated for the preliminary investigation of their electrochromic applications.

Two series of polyamides and polyimides containing bulky trityl-substituted triphenylamine units were synthesized from condensation reactions of 4,4′-diamino-4′′-trityltriphenylamine with various dicarboxylic acids and tetracarboxylic dianhydrides, respectively. The polymers showed good solubility and film-forming ability. Flexible or robust films could be readily obtained via solution-casting. The use of aliphatic diacid or dianhydride reduces interchain charge transfer complexing and leads to colorless polyamide and polyimide films. These polymers showed glass-transition temperatures in the range of 206–336 °C. Cyclic voltammograms of the polyamide and polyimide films displayed reversible electrochemical oxidation processes in the range of 0–1.0 or 0–1.3 V. Upon oxidation, the color of polymer films changes from colorless to blue-green or blue. As compared to the polyimide counterparts, the polyamides showed lower oxidation potentials and thus a higher electrochromic stability and coloration efficiency. Simple electrochromic devices were also fabricated as a preliminary investigation for electrochromic applications of the prepared polymers.

Two bisimide compounds, TPA–TPDI and NPC–TPDI, consisting of a triptycene core and two triphenylamine (TPA) or N-phenylcarbazole (NPC) end groups were successfully synthesized by the condensation reactions from 1,4-bis(3,4-dicarboxyphenoxy)triptycene dianhydride with 4-aminotriphenylamine and N-(4-aminophenyl)carbazole, respectively. These two monomers could polymerize electrochemically via the oxidative coupling reactions of triarylamine units. The electrochemical and spectroelectrochemical properties of the electro-generated triptycene poly(ether-imide)s (TPA–TPPI and NPC–TPPI) were studied. Both polymers have two colored oxidation states, and TPA–TPPI showed better electrochromic performance than NPC–TPPI.