Tuning the Negative Photochromism of Water-Soluble Spiropyran Polymers
| Autor: | Samuel W. Thomas, Matthew J. Feeney |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Spiropyran
chemistry.chemical_classification Polymers and Plastics Comonomer Organic Chemistry Cationic polymerization Protonation 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences 0104 chemical sciences Inorganic Chemistry chemistry.chemical_compound Photochromism chemistry Yield (chemistry) Materials Chemistry Copolymer 0210 nano-technology |
| Zdroj: | Macromolecules. 51:8027-8037 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/acs.macromol.8b01915 |
| Popis: | In aqueous media, negative photochromism can occur from cationic, protonated merocyanines (MCH+) to spiropyrans (SP) upon exposure to visible light. Herein, we demonstrate the uniquely simple manner in which polymers can tune the key properties of these photochromes through copolymer preparation. Nine water-soluble, SP-containing polymers yield wide ranges of key properties for negative photochromism—accessible MCH+ pKa values spanning 5 pH units, quantum yields of photochemical ring closure up to 0.2, and rates of thermal equilibration ranging 2 orders of magnitude. In buffered solutions, many of these polymers showed photostationary states with greater than 80% conversion to SP and no detectable photochromic fatigue over 15 cycles. These results demonstrate the potential for tuning key properties of the MCH+ photochrome through both the spiropyran pendants themselves and the water-solubilizing comonomers. The dependence of MCH+ pKa on comonomer structure enabled tunable range of pH for reversible photoa... |
| Databáze: | OpenAIRE |
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