Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 120-750, Republic of Korea.
J Phys Chem B. 2009 Dec 31;113(52):16508-12. doi: 10.1021/jp908430w.
The fluorescence quantum yield of 9-dicyanovinyljulolidine (DCVJ) is very low in fluid solutions but increases markedly in solids because the medium rigidity slows down the internal motion, which acts as a major nonradiative decay channel. In this work, the excited-state twisting motion of DCVJ in polymers was investigated by time-resolved fluorescence spectroscopy, and it was observed that the fluorescence lifetime of DCVJ in polymers depends on the mechanical properties of the medium. Therefore, our results indicate that the elastic modulus is a determining factor for molecular rotor dynamics in soft matter, and its description requires a comprehensive visco-elasto-plastic theory.
9-二氰基乙烯基芴（DCVJ）的荧光量子产率在流体溶液中非常低，但在固体中显著增加，因为介质刚性降低了内部运动，内部运动是主要的非辐射衰减通道。在这项工作中，通过时间分辨荧光光谱研究了 DCVJ 在聚合物中的激发态扭转运动，观察到 DCVJ 在聚合物中的荧光寿命取决于介质的机械性能。因此，我们的结果表明，弹性模量是软物质中分子转子动力学的决定因素，其描述需要一个全面的粘弹性塑性理论。
