A novel semi-aromatic polyamide with bis(diphenylamino)-fluorene moieties was designed and synthesized, which exhibited highly stable electrochromic/electrofluorescent dual-switching properties.

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a b s t r a c tIn this work, a series of AEE-active polyamides containing methylsulfonyltriphenylamine units were prepared from a newly synthesized diamine "4,4 0 -diamine-4 00 -methylsulfonyltriphenylamine" and three dicarboxylic acids, which were highly soluble in various organic solvents and exhibited outstanding thermostability. The resulting polymer films showed one reversible redox couple along with apparent color changing from colorless to purple. The polymer solutions revealed relatively weak fluorescence with quantum yields in the range of 2.2e26.2%, which could be enhanced by induced aggregation in poor solvents. Furthermore, the bright fluorescence of the solid polymer film could be reversibly tuned by direct electrochemical redox of triphenylamine with a high contrast ratio (I off /I on ) of 234. Overall, this comprehensive investigation of their interesting electrochromic and electrofluorochromic bifunctional properties not only supplies a deep understanding of the optical essence upon electrical stimuli but also paves the way for their future intelligent applications.

Two kinds of polyarylates with diphenylamine-fluorene units were synthesized from the bisphenol monomer “ N, N-di(4-hydroxyphenyl)-2-amino-9,9-dimethylfluorene” with two different benzenedicarbonyl chlorides. These polyarylates were highly soluble in N, N-dimethylacetamide, tetrahydrofuran, and chloroform and could be easily solution-cast into transparent films. Both of the polyarylates exhibited a couple of reversible redox with half-wave potentials in the range of 0.87–0.90 V. During the electrochromic process, the color of the film changed from colorless (neutral state) to grey green (oxidation state) with a high coloration efficiency of 242 cm2 C−1. Compared with the polyarylates prepared from terephthaloyl chloride, the polyarylates prepared from isophthaloyl chloride exhibited enhanced fluorescence because of the reduced charge-transfer effect. Furthermore, its fluorescence could be reversibly switched under the applied potentials.