pH值和无机盐对DMP临界胶束浓度的影响

Influencing of pH and Inorganic Salt on the Critical Micelle Concentration of Dodecylmorpholine

在(20±0.5)℃下,采用表面张力法考察了不同无机盐(NaCl、KCl、MgCl_2、CaCl_2)和pH值对十二烷基吗啉(DMP)临界胶束浓度(CMC)的影响。实验结果表明,随着溶液pH值的增大,DMP的CMC减小。无机盐浓度增大,DMP的CMC减小;对同主族元素,无机盐阳离子浓度相同时,离子半径越大,CMC减小的趋势越明显;对于不同价态无机盐阳离子,离子价态越高,CMC减小的趋势越明显。机理分析表明,无机盐阳离子对CMC值的影响不仅和无机盐水合阳离子对表面活性剂离子头基的屏蔽作用有关,而且受阳离子的"盐析效应"影响。

At（ 20 ± 0. 5） ℃,the CMC value of dodecylmorpholine in the aqueous solution under the presence of HCl and inorganic salt（ NaCl,KCl,MgCl_2,CaCl_2） was measured by the method of surface tension. The experiment results showed that the CMC value of DMP decreased with the increase of the solution pH value. The CMC value of DMP decreased with the increase of the inorganic salt concentration. With the same main group element,the ionic radius is greater,the CMC value decreased more obvious when the concentration of inorganic salt cationic was consistent.For different valence inorganic cationic,the ion valence is higher when the CMC value decreased trend will be more obvious. Mechanism analysis showed that the influence of inorganic salt cationic on CMC value not only was related with hydration cation on the shielding effect of the surfactant ions head,but also affected by ＂salting out effect＂.