Click synthesis and reversible electrochromic behaviors of novel polystyrenes bearing aromatic amine units

Article abstract of DOI:10.1002/pola.25990

Novel electrochromic polymers were prepared by the click postfunctionalization of poly(4-azidomethylstyrene) with alkyne-containing aromatic amine units in the presence of Cu(I) catalysts. Two kinds of aromatic amine units, tris(4-alkoxyphenyl)amine and N,N,N',N'-tetraphenyl-p- phenylenediamine, were introduced into polystyrene side chains, which were completely characterized by gel permeation chromatography-multiangle light scattering, nuclear magnetic resonance, and infrared spectroscopies, and elemental analysis. Thermal analyses demonstrated the high stability with the decomposition temperatures exceeding 300 °C even after postfunctionalization. The UV-vis absorption spectra of the polymer thin films revealed negligible absorption in the visible region, as reasonably confirmed by visual observation. The polymer thin films were prepared by spray-coating on an indium tin oxide-coated glass plate. Cyclic voltammograms of these films exhibited anodic peaks ascribed to the oxidation of the side-chain aromatic amine moieties. The tris(4-alkoxyphenyl)amine unit displayed one-step oxidation at 0.287 V (vs. Ag/AgCl), while the N,N,N',N'-tetraphenyl-p-phenylenediamine unit showed two-step oxidations at 0.297 and 0.641 V. These oxidation processes produced new colors of the polymer films. The former triarylamine-based chromophore provided a blue color after the oxidation, while the latter phenylenediamine-based chromophore showed a potentially controlled green and dark blue colors. The reversibility and switching behaviors of these color changes were also comprehensively investigated. 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 Aromatic amine-based active electrochromophores were quantitatively introduced into a polystyrene side chain by using the Cu(I)-catalyzed azide-alkyne cycloaddition reaction. The reversible electrochromic behaviors of the functionalized polystyrenes were investigated by spectroelectrochemistry. Copyright