自发射荧光猝灭测定Gemini阴离子表面活性剂胶团聚集数

Gemini表面活性剂C11pPHCNa分子联接链上的对苯氧基在激发下自发射荧光。当浓度超过0.45 mmol·L-1时，激发光谱谱带的拓扑结构发生一系列变化，导致不同于对应的吸收光谱。由于联接链上的对苯氧基明显猝灭了外加探针芘发射的荧光，所以不能用传统的方法测定这类胶团的聚集数。文章利用甲基紫精(MV2+)可有效猝灭C11pPHCNa分子自发射荧光的原理，建立了测定这类胶团平均聚集数的方法。由该方法获得C11pPHCNa胶团平均聚集数为20.6;在溶液体相摩尔比为3∶7的C11pPHCNa/C₁₂-S₂-E₁-C₁₂·2Br体系中，混合胶团的平均聚集数为11.8。

Aggregation Number Determination of Gemini Anionic Surfactant Micelle by Intrinsic Fluorescence Quenching

The p-phendioxyl base in the spacer of gemini surfactant C11pPHCNa emits fluorescence under exciting. When the gemini concentration is over 0.45 mmol x L(-1), the topological structure of the excitation spectra yields various changes resulting in them being significantly different from the corresponding absorption spectra. As the aromatic base in the spacer of C11pPHCNa obviously quenches the fluorescence of pyrene that is as additional probe, it is hardly to determine the average micelle aggregation number by the usual method of quenching pyrene. In the present paper, using the property of methylviologen (MV2+) effectively quenching the fluorescence of C11pPHCNa, the authors established the method to determine the average aggregation number N of C11pPHCNa micelle. For individual C11pPHCNa micelle, N was determined to be 20.6 at c=2 mmol L(-1), while the average aggregation number of C11pPHCNa/C12-2-E1-C12 x 2Br mixed micelle in the aqueous solution with a total concentration of 2 mmol x L(-1) and C11pPHCNa of mole fraction 0.3 in the bulk was obtained to be 11.8.