Transparent-to-colored electrochromic devices exhibit promising application prospects and have gained popularity. Herein, two triphenylamine derivatives TPA-OCH 3 and TPA-CN with styryl moieties and different donor or acceptor units were designed and synthesized to further prepare solvent-resistant thermally cross-linking polymer P(TPA-OCH 3 ) and P(TPA-CN) without any additional initiator. P(TPA-OCH 3 ) and P(TPA-CN) possess two pairs of redox peaks, and P(TPA-OCH 3 ) shows a lower onset oxidation potential compared to P(TPA-CN) because of the pendent donor unit. Correspondingly, both polymers exhibit multicolored changes from the neutral colorless state to noticeable oxidized colors under different potentials. Furthermore, the thermally cross-linking copolymer P(TPA-OCH 3 -co-TPA-CN) was obtained by TPA-OCH 3 and TPA-CN (the molar ratio is 2:1) and presents outstanding electrochromism with four color changes (colorless−orange−blue−purple) due to the multistep redox process of TPA-OCH 3 and TPA-CN units. It is more intriguing that the electrochromic device based on the copolymer films possesses a high optical contrast of 57.8% at 680 nm, fast switching time (0.52 and 0.66 s), and robust cyclic stability over 30 000 cycles with very little decay. Therefore, the thermally cross-linking copolymer is a promising candidate material for high-performance transmittive electrochromic devices, such as smart windows, sunglasses, and E-papers.
Pyrene-containing water-soluble probes for the fluorescent detection of nitroaromatic compounds (NACs), such as explosive components (2,4-DNT and 2,4,6-TNT) and herbicides (2,4-dinitrocresol, 2,4-DNOC), in aqueous media are reported. In the probes, the introduction of surface-active hydrophilic "heads" at the periphery of lipophilic (i.e., hydrophobic) pyrene "tails" resulted in the formation of highly fluorescent micelle-like aggregates/pre-associates in aqueous solutions at concentrations of ≤10(-5) m. The enhanced fluorescence quenching of the herein reported architectures is achieved in the presence of ultra-trace amounts of TNT or 2,4-DNT with values of Stern-Volmer quenching constant close to 1×10(5) m(-1) and a detection limit as low as 182 ppb. The most hydrophilic probes demonstrated higher response to 2,4-DNT over TNT. Filter paper test strips impregnated with 1×10(-5) m solutions of the probes were able to detect TNT, 2,4-DNT, and other NACs at levels as low as 50 ppb in water.
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