Visualization and Quantitative Evaluation of Mechanoradicals Using Fluorescent Radical Precursors in the Bulk State
발표자
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초록
내용
The detection of polymeric mechanoradicals generated by homolytic cleavage of polymer chains in response to mechanical stress is still limited in the bulk state owing to their high reactivity. Herein, we propose a strategy to detect polymeric mechanoradicals visually and quantitatively using a diarylacetonitrile (H-DAAN) moiety, which can work as a radical transfer agent for polymeric radicals and generate yellow fluorescent radical species (DAAN•). Ball-milling tests on the mixture of polystyrene and H-DAAN showed yellow fluorescence derived from DAAN• evaluated by fluorescence measurement (λem = 556 nm) and electron paramagnetic resonance measurement (g = 2.003). The mechanism of mechanical degradation is supported by the linear correlation between the amount of generated DAAN• and the fluorescence intensity. We have also succeeded in introducing H-DAAN moiety into the side chains of polystyrene and achieved to add the function to detect main chain scission.