黑皂膜中染料分子的共振Raman光谱及其分子取向

本文研究了BSF中染料BY和MO分子的取向问题, 建立了三点式数据采集方法,测得各种入射角θ下BSF中BY和MO分子的-N=N-对称伸缩振动谱带的Raman偏振比R~1和R~2, 分别用单轴唯一角取向模型和取向分布模型, 讨论偏振比R~1和R~2与入射角θ的关系。单轴唯一角取向模型处理上述偏振数据的结果表明, BY以较大的倾角(约80°)斜躺在BSF的膜壁上; 凝胶相的BSF中, MO取向角约为70°, 随温度升高,BSF转变为液晶相对, MO的取向角减小到65°。用取向分布模型处理, 得到染料分子的取向分布图象, BY和MO在BSF中均以90°取向几率为最大, 但其它各方向亦有一定的取向几率, BSF的相变导致MO分子的取向分布图象由较为集中型转变为更加弥散型。

Polarized raman study on molecular onentation of azo dyes in black soap films

In order to study the mol. orientation of brilliant yellow (BY) and methyl orange (MO) in black soap (cationic surfactant) films with resonance Raman spectra, three-point datum collection method (collecting polarized Raman scattering intensity data at three point, i.e., two datum line points and one peak point) was set up to measure the polarized ratios of the -N=N- stretching vibration band at various incident angles. The theor. relations were discussed between the two ratios and the incident angle for the uniaxial orientation model and orientation distribution model,resp. By fitting the experimental data of the polarized ratios with the uniaxial orientation model, it was discovered that BY was laid down the interface of black soap films (tilt angle ~80? and the tilt angle of MO decreased from 70?to 65?when the black soap film took the gel-to-liq. crystal phase transition. From the fitting results with the orientation distribution model, the orientation distribution graphs of the long axis of the azo dyes were given. BY and MO were mainly laid down the film plane, but there were some orientation probabilities in other directions, and the gel-to-liq. crystal phase transition resulted in a decrease in the orientational order of MO.