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Conjugated Polyelectrolytes Designed for Biological Applications
Published in John R. Reynolds, Barry C. Thompson, Terje A. Skotheim, Conjugated Polymers, 2019
Pradeepkumar Jagadesan, Yun Huang, Kirk S. Schanze
Only a few examples of CPEs with anionic phosphonate groups have been reported in the literature. PPE based CPE 6.1, having phosphonate pendant groups reported by Pinto and Schanze, is highly water-soluble and absorbs UV-light with λmax ∼ 415 nm and features a moderately intense fluorescence with λmax ∼ 438 nm at pH = 12.[32] However, at pH = 7.5, the absorption band of 6.1 red shifts to λmax ∼ 445 nm, and the fluorescence band becomes broad with λmax ∼ 510 nm due to aggregation. Polyelectrolyte 6.1 displays “amplified quenching” towards MV2+ and rhodamine 6G. Ultrathin multilayer films fabricated using 6.1 and Zr(VI) exhibit electroluminescence with a turn-on voltage between 5 and 6 V. The polythiophene-type CPE with phosphonate groups 6.2 exhibits an absorption maximum at 496 nm and undergoes electrochemical oxidation in aqueous solution.[33] Polyelectrolyte 6.2 displays self-acid doping at pH below 13, and the multilayer films fabricated using it with Zr(IV) ions exhibit both electrochromism and pH-induced halochromism.
Smart textiles: an overview of recent progress on chromic textiles
Published in The Journal of The Textile Institute, 2021
Heloisa Ramlow, Karina Luzia Andrade, Ana Paula Serafini Immich
Halochromic textiles change color when pH changes occur. Smart textiles for pH detection can be useful for the determination of alkaline or acidic conditions. Mao et al. (2018) developed a stimuli-responsive polymeric dye based on waterborne polyurethane and azobenzene chromophore and applied it on a cotton fabric via coating. The dyed fabric acquired the ability to respond to acid condition (acidochromic) and UV radiation (photochromic). The maximum absorption peak of the polymeric dye and its coated fabric shifted from 410 nm to 520 nm upon pH decreasing from 6 to 1, accompanying with the pronounced color change from yellow to amaranth with an excellent fatigue resistance due to structural transition from diazo to hydrazone form. The authors observed that the color of the polymeric dye and its coated fabric can be reversibly switched via adjusting pH value.