Abstract

Photophysical processes in water-micellar solutions of fluorescein have been studied using the methods of stationary time-resolved fluorescence spectroscopy and dynamic light scattering. It has been found that the introduction of dye molecules into reverse micelles causes an increase in their hydrodynamic radii \(R_{h}\), proportional to the degree of hydration \(w\). The absorption and fluorescence spectra, the average lifetime of the excited state \(t\), and the degree of fluorescence anisotropy \(r\) of the fluorescein molecules are presented for different values of \(R_{h}\). It has been found that with the growth of \(R_{h}\), the fraction of the anionic form of the dye in water-micellar solutions increases. In this case, an increase in the ratio of the dipole moments of the fluorescein molecules in the excited and ground states \(\mu_{e}\)/\(\mu_{g}\) is observed, due to the structural reorganization of micelles. It has been experimentally established that the rotational relaxation time \(\theta\) of dye molecules decreases with growing \(R_{h}\), which indicates an increase in the microviscosity of the environment of the fluorescein molecules due to the localization of dye molecules in the region of surface water in the micelle.

中文翻译：

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纳米级反胶束对荧光素分子光物理性质的影响

摘要

使用固定时间分辨荧光光谱法和动态光散射方法研究了荧光素水胶束溶液中的光物理过程。已经发现，将染料分子引入反胶束会导致它们的流体力学半径\（R_ {h} \）增大，与水合度\（w \）成正比。对于不同的\（R_ {h} \）值，给出了荧光素分子的吸收光谱和荧光光谱，激发态的平均寿命（t \）以及荧光各向异性程度（r \）。已经发现随着\（R_ {h} \）的增长，染料在水-胶束溶液中的阴离子形式的比例增加。在这种情况下，由于结构重组，观察到荧光素分子在激发态和基态\（\ mu_ {e} \） / \（\ mu_ {g} \）中偶极矩比的增加。胶束。实验已经确定，染料分子的旋转弛豫时间\（\ theta \）随着\（R_ {h} \）的增加而减小，这表明由于胶束中地表水区域中的染料分子。