STUDY OF pNa OF AQUEOUS SOLUTIONS OF SODIUM DECYL, DODECYL, AND TETRADECYL SULFATES BY E.M.F. MEASUREMENTS
STUDY OF pNa OF AQUEOUS SOLUTIONS OF SODIUM DECYL, DODECYL, AND TETRADECYL SULFATES BY E.M.F. MEASUREMENTS
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电动势研究癸基、十二烷基和十四烷基硫酸钠水溶液的 pNa
DOI：
10.1021/j100804a026
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发表时间：
1963
期刊：
影响因子：
--
通讯作者：
M. B. Epstein
中科院分区：
文献类型：
--
作者：
L. Shedlovsky;C. Jakob;M. B. Epstein
用钠响应玻璃电极和饱和KCl、甘汞电极在烷基硫酸钠混合物上作电动势测定。研究了两种溶液对：癸基和十二烷基硫酸钠和十二烷基和十四烷基硫酸钠。临界胶束浓度选自pNa对log c的曲线。用Mysels和Otter的方法确定了混合物胶束溶液中的非胶束浓度。钠反离子的胶束的解离的程度估计从减少的数据。根据活度系数，除了癸基硫酸钠含量大于25%（摩尔）的混合物外，所有混合物在临界胶束浓度以下都有较强的相互作用。Botré、Crescenzi和Mele1使用阳离子有机膜对几种单一胶体电解质溶液进行了类似的测量。在他们的讨论中，他们将胶束视为聚电解质。胶体电解质的胶束溶液通常被视为准相体系，一种是水性或非胶束介质，其中分布着第二种胶束。Lange2指出，在含有两种表面活性溶质的胶束体系中，临界胶束浓度（cmc）随两种溶质的相对量而变化，cmc的位置是水介质的一种相边界。在理论模型的基础上，Mysels和Otter最近采用电导率测量方法，得到了混合胶束的边界和与水介质的连接线，并讨论了体系的热力学。在对它们的处理中隐含着它可以适用于其他密集型财产。我们已经使用电动势测量建立胶束的组成，并延长治疗Botré，Crescenzi，和Meleto混合系统。
Electromotive forcemeasurements were made with sodium-responsive glass electrodes and saturated KC1, calomel electrodes on mixtures of sodium alkyl sulfates. Two solution pairs were studied: sodium decyl and dodecyl sulfates and sodium dodecyl and tetradecyl sulfates. Critical micelle concentrations were selected from plots of pNa vs. log c. The procedure of Mysels and Otter was used toestablish the non-micellar con-centrations in the micellar solutions of mixtures. The extent of the dissociation of sodium counterions by the micelles was estimated from the reduced data. From the activity coefficients strong interaction below the critical micelle concentration was inferred for all the mixtures except those containing more than 25 mole% of sodium decyl sulfate.The present investigation examines the behavior of aqueous solutionsof mixed colloidal electrolytes by means of electromotive force (emf) measurements based on a sodium-responsive glass electrode. Botré, Crescenzi, and Mele1 carriedout similar measurements for solutions of a few single colloidal electrolytes by using cationic organic membranes. In their discussion they treated the micelles as polyelectrolytes. It often is convenient to treat micellar solutions of colloidal electrolytes as a system of quasi-phases, one, an aqueous or non-micellar medium, within which a second, the micelles, is distributed. Lange2 recog-nized that in a micellar system, which contains two sur-face active solutes, the critical micelle concentration (cmc) varies with the relative amounts of the two solutes and that the locus of the cmc was a kind of phase boundary of theaqueous medium. On the basis of a theoretical model, Mysels and Otter3 recently em-ployed conductivity measurements to obtain the boundary of the mixed micelles and the tie lines to the aque-ous medium; they discussed also thethermodynamics of the system. It is implicit in their treatment that it may be applied to other intensive properties. We have used emf measurements both to establish the composition of the micelles and to extend the treatment of Botré, Crescenzi, and Meleto mixed systems.