DMABN测定含溴化钠或正丁醇水溶液中表面活性剂的临界胶团浓度

以对二甲氨基苯甲腈(DMABN)为探针, 测定它在含NaBr或n-C4H9OH的表面活性剂十二烷基三甲基溴化铵(C12TABr)、季铵盐Gemini表面活性剂C12-3-C12·2Br和十二烷基硫酸钠(SDS)水溶液中的第二重荧光对应的强度(Ia)和特征波长(λa)对表面活性剂浓度(c)曲线. 由Ia-c曲线的转折点或λa-c曲线对应的一阶导数极小点可以获得临界胶团浓度(cmc), 扩展了DMABN探针测定表面活性剂cmc的适用性.

Determination of the Critical Micelle Concentration of Surfactant in Aqueous NaBr or n-Butanol Solution by DMABN

With p-N,N-dimethylaminobenzonitrile (DMABN) as probe, the variations of the intensity of its second fluorescence emission (Ia) and the corresponding characteristic wave-length (λa) with the surfactant (dodecyltrimethyl-ammonium bromide C12TABr, quaternary ammonium Gemini surfactant C12-3-C12·2Br and sodium dodecylsulfate SDS) concentration (c) in NaBr-containing or n-C4H9OH-containing aqueous solution were measured by a Hitachi F4500 fluorescence spectrophotometer. The results showed that the break point on the Ia-c curve and the minimum of the derivative variation corresponding to the λa-c curve agreed well with the critical micelle concentration (cmc) of the surfactant. This extends the range of DMABN as probe to measure the cmc of surfactant.