紫外吸收分光光度法测定表面活性剂的临界胶束浓度

Determination of CMC of Surfactants with UV-vis Absorption Spectrophotometry

中文关键词:  CMC  表面活性剂  UV  NMR

英文关键词:CMC  surfactants  UV  NMR

中文摘要:

      应用紫外吸收分光光谱(UV法,用N,N-二乙基苯胺(DEA)为探针,测定了不同类型表面活性剂的临界胶束浓度(CMC).并用1HNMR波谱确定了DEA在胶束中增溶位置.结果表明,表面活性剂浓度高于CMC时,DEA增溶于胶束内核的碳氢环境中,DEA的最大吸收波长(λmax)接近于其正在辛烷中的值,而浓度低于CMC时,λmax值接近于其在水中的值.紫外吸收范围内,DEA在不同表面活性剂浓度时的最大吸收波长(λmax)对表面活性剂浓度的曲线转折点即为临界胶束浓度(CMC).

英文摘要:

      The critical micelle concentrations of different surfactants(CTAB,As,AOT,C 12 BE,C 14 BE,As-CTAB,and AOT-CTAB mixtures) were determined by using UV-vis absorption spectrphotometry,and the N,N-diethylaniline(DEA) is used to be the ultraviolet absorption probe in the CMC measurements. At the same time,the solubilization site of DEA in a micelle was investigated by 1 H NMR spectra,and it was foud that DEA is solubilized in the core of a micelle. The difference between λ max of DEA at above the CMC approached the value in n-octane and at below the CMC approached the Value in water. The concentration at the distinct break point for the curve of λ max vs surfactant concentrations was the CMC value of surfactant.