Single molecule probing of dynamics in supercooled polymers.
Single molecule probing of dynamics in supercooled polymers.
复制标题
过冷聚合物动力学的单分子探测。
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
R. Vallée
中科院分区：
文献类型：
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作者：
G. Hinze;T. Basché;R. Vallée
在过冷区，用单分子BODIPY嵌入聚丙烯酸甲酯基质，在不同温度下进行了荧光实验。通过脉冲激发，可以同时获得荧光寿命和线性二向色性时间轨迹。这两个可观测数据都是在没有数据入库的情况下进行分析的。虽然线性二色性只反映单个粒子的动力学，但可观察到的荧光寿命取决于分子环境，因此来自发色团周围的聚合物宿主的动力学对这个量有贡献。我们观察到寿命关联的衰减略快于极化关联，这表明发生了大的角度重定向。此外，还引用了二色性时间轨迹来直接揭示转动动力学的几何形状。我们发现，较小但也明显较大的旋转跳跃负责整个分子的重新定向。
Fluorescence experiments with single BODIPY molecules embedded in a poly(methyl acrylate) matrix have been performed at various temperatures in the supercooled regime. By using pulsed excitation, fluorescence lifetime and linear dichroism time trajectories were accessible at the same time. Both observables have been analyzed without data binning. While the linear dichroism solely reflects single particle dynamics, the fluorescence lifetime observable depends on the molecular environment, so that the dynamics from the polymer host surrounding a chromophore contributes to this quantity. We observe that the lifetime correlation decays slightly faster than polarization correlation, indicating the occurrence of large angular reorientations. Additionally, dichroism time trajectories have been adducted to reveal directly the geometry of rotational dynamics. We identify small but also significantly larger rotational jumps being responsible for the overall molecular reorientation.