离子/非离子混合表面活性剂体系的热力学研究
Thermodynamic studies of mixed ionic/nonionic surfactant systems.
作者信息
Razavizadeh B M, Mousavi-Khoshdel M, Gharibi H, Behjatmanesh-Ardakani R, Javadian S, Sohrabi B
机构信息
Department of Chemistry, Khorassn Science and Technology Park, P.O. Box 91735-139, Mashhad, Iran.
出版信息
J Colloid Interface Sci. 2004 Aug 1;276(1):197-207. doi: 10.1016/j.jcis.2004.03.036.
Mixtures of alkyltrimethylammonium bromide (CnTAB, n=12, 14, 16, 18) and Triton X-100 were studied at a range of mole fractions of ionic surfactant per nonionic surfactant. For each mixture, the cmc obtained from surface tension measurements differed from that obtained using potentiometry. The behavior of these mixed-surfactant systems showed three different regions with increasing total surfactant concentration. From the surface tension and potentiometry data, we obtained the free monomer concentration of ionic surfactant (mi), the micellar mole fraction of surfactant (xi), and the degree of dissociation (alpha) of ionic surfactant. We also obtained the free monomer concentration of Triton X-100 (m2) using PFG-NMR technique. A new equation was introduced to evaluate the activity coefficient in the micellar phase. The excess free energy (GE) and the synergetic parameters of mixtures were determined at various mole fractions of CnTAB/Triton X-100. Finally, the complexity of the synergism parameters was investigated.
研究了烷基三甲基溴化铵（CnTAB，n = 12、14、16、18）与 Triton X - 100 在一系列离子表面活性剂与非离子表面活性剂摩尔分数下的混合物。对于每种混合物，通过表面张力测量得到的临界胶束浓度（cmc）与使用电位滴定法得到的结果不同。随着总表面活性剂浓度的增加，这些混合表面活性剂体系的行为表现出三个不同区域。根据表面张力和电位滴定数据，我们得到了离子表面活性剂的游离单体浓度（mi）、表面活性剂的胶束摩尔分数（xi）以及离子表面活性剂的解离度（α）。我们还使用脉冲场梯度核磁共振（PFG - NMR）技术得到了 Triton X - 100 的游离单体浓度（m2）。引入了一个新的方程来评估胶束相中的活度系数。在 CnTAB/Triton X - 100 的不同摩尔分数下测定了混合物的过量自由能（GE）和协同参数。最后，研究了协同参数的复杂性。
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