Dynamic Polymer Free Volume Monitored by Single-Molecule Spectroscopy of a Dual Fluorescent Flapping Dopant
| Autor: | Shun Omagari, Kensuke Suga, Ryo Achiwa, Martin Vacha, Yuma Goto, Ryuma Sato, Shohei Saito, Nilanjan Dey, Takuya Yamakado |
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| Rok vydání: | 2021 |
| Předmět: |
Dopant
Molecular Structure General Chemistry Molecular Dynamics Simulation Biochemistry Molecular physics Catalysis Single Molecule Imaging chemistry.chemical_compound Cyclooctanes Colloid and Surface Chemistry chemistry Excited state Chemical-mechanical planarization Flapping Molecule Phenazines Polystyrenes Polystyrene Spectroscopy Glass transition Fluorescent Dyes |
| Zdroj: | Journal of the American Chemical Society. 143(35) |
| ISSN: | 1520-5126 |
| Popis: | Single-molecule spectroscopy (SMS) of a dual fluorescent flapping molecular probe (N-FLAP) enabled real-time nanoscale monitoring of local free volume dynamics in polystyrenes. The SMS study was realized by structural improvement of a previously reported flapping molecule by nitrogen substitution, leading to increased brightness (22 times) of the probe. In a polystyrene thin film at the temperature of 5 K above the glass transition, the spectra of a single N-FLAP molecule undergo frequent jumps between short- and long-wavelength forms, the latter one indicating planarization of the molecule in the excited state. The observed spectral jumps were statistically analyzed to reveal the dynamics of the molecular environment. The analysis together with MD and QM/MM calculations show that the excited-state planarization of the flapping probe occurs only when sufficiently large polymer free volume of more than, at least, 280 A3 is available close to the molecule, and that such free volume lasts for an average of 1.2 s. |
| Databáze: | OpenAIRE |
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