pH值对亮黄水溶液及CTAB胶束溶液共振Raman光谱的影响

Effect of pH Values on Resonance Raman Spectra of Brilliant Yellow in Aqueous and CTAB Micella Solutions

我们曾研究了黑皂膜的界面性质,为深入了解pH对偶氮苯类化合物在水溶液中及胶束表面上结构变化的影响,本文选用亮黄(BY)为谱学探针,仔细考察了其水溶液及溴化十六烷基三甲铵(CTAB)胶束溶液的共振Raman光谱,根据谱带指认,描述了由酸碱性导致的BY分子的结构变化,其中包括共振体间平衡和酸碱平衡。

Resonance Raman spectra of brilliant yellow (BY) in aqueous and cetyltrimethylammonium bromide (CTAB) micella solutions were measured at various pH values. Two spectral patterns under acidic and basic conditions are ascribed to correspond azo and quinoid forms of BY, respectively, which can be employed as a measure of the surface potentical and microenvironment of the micelle . According to Heeseman, the pKa= [pKa(surface) -pKa(aqueous)] is estimated to be about 0. 8 and is related to the change of the surface potential.