SEBS分子链在不同溶剂中的荧光特性

Fluorescent Characteristics of SEBS Chains in Different Solvents

利用荧光光谱法对SEBS分子链在不同溶剂中的荧光特性进行了分析。研究表明,室温下,SEBS在四氢呋喃和环己烷中的荧光发射波长为380 nm,且为本征荧光;而在甲苯溶液中的发射波长为375 nm,相对于本征荧光蓝移动了5 nm。在共振散色光谱中,3种体系的共振光强度都是随着溶液浓度的增大呈线性增加,但甲苯溶液体系共振散色光强度的变化较缓慢。造成这些现象的原因在于四氢呋喃和环己烷分子中没有苯环结构,不具备荧光发射的条件,因而SEBS在这两种溶剂中具有本征荧光效应;而甲苯和SEBS都具有苯环结构,相邻的苯环间通过π电子的相互重叠形成T型结构的二聚体,导致了荧光强度的减弱和共振散色光强度变化较缓慢。

The fluorescent characteristics of SEBS chains in different solvents were studied by using fluorescence spectrometry. The results showed that the intrinsic fluorescence of SEBS could be found in tetrahydrofuran and cyclohexane solvent, and the emission wavelength was around at 380 nm. However, the emission wavelength shifted from 380 to 375 nm when SEBS dissolved in the toluene. In addition, the intensity of resonance scattering spectrum of SEBS increased with the increase of solution concentration. The reason for these phenomena was that there was no benzene ring structure in tetrahydrofuran and cyclohexane molecules, and it did not possess the conditions of fluorescence emission. Therefore, SEBS had intrinsic fluorescence effect in these two solvents. Oppositely, presence of benzene ring in toluene and SEBS could lead the formation of dimmers with T structure, resulting in a decrease in fluorescence intensity and a slow change in resonance light intensity.