Paul Bidyut K, Mitra Rajib K
Geological Studies Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata 700108, India.
J Colloid Interface Sci. 2005 Aug 1;288(1):261-79. doi: 10.1016/j.jcis.2005.02.088.
Solubilization of water in mixed reverse micellar systems with anionic surfactant (AOT) and nonionic surfactants (Brijs, Spans, Tweens, Igepal CO 520), cationic surfactant (DDAB)-nonionic surfactants (Brijs, Spans, Igepal CO 520), and nonionic (Igepal CO 520)-nonionics (Brijs, Spans) in oils of different chemical structures and physical properties (isopropyl myristate, isobutyl benzene, cyclohexane) has been studied at 303 K. The enhancement in water solubilization has been evidenced in these systems with some exceptions. The maximum water solubilization capacity (omega(0,max)) in mixed reverse micellar systems occurred at a certain mole fraction of a nonionic surfactant, which is indicated as X(nonionic,max). The addition of electrolyte (NaCl or NaBr) in these systems tends to enhance their solubilization capacities further both at a fixed composition of nonionic (X(nonionic); 0.1) and at X(nonionic,max) at 303 K. The maximum in solubilization capacity of electrolyte (omega(max)) was obtained at an optimal electrolyte concentration (designated as NaCl or NaBr). All these parameters, omega(0,max) vis-a-vis X(nonionic,max) and omega(max) vis-a-vis NaCl, have been found to be dependent on the surfactant component (content, EO chains, and configuration of the polar head group, and the hydrocarbon moiety of the nonionic surfactants) and type of oils. The conductance behavior of these systems has also been investigated, focusing on the influences of water content (omega), content of nonionics (X(nonionic)), concentration of electrolyte ([NaCl] or [NaBr]), and oil. Percolation of conductance has been observed in some of these systems and explained by considering the influences of the variables on the rigidity of the oil/water interface and attractive interactions of the surfactant aggregates. Percolation zones have been depicted in the solubilization capacity vs X(nonionic) or [electrolyte] curves in order to correlate with maximum in water or electrolyte solubilization capacity. The overall results, obtained in these studies, have been interpreted in terms of the model proposed by Shah and co-workers for the solubility of water in water-in-oil microemulsions, as their model proposed that the two main effects that determine the solubility of these systems are curvature of the surfactant film separating the oil and water and interactions between water droplets.
在303K下，研究了水在具有不同化学结构和物理性质的油（肉豆蔻酸异丙酯、异丁基苯、环己烷）中的混合反胶束体系中的增溶作用，这些体系包括阴离子表面活性剂（AOT）与非离子表面活性剂（Brij、Span、Tween、Igepal CO 520）、阳离子表面活性剂（DDAB）-非离子表面活性剂（Brij、Span、Igepal CO 520）以及非离子表面活性剂（Igepal CO 520）-非离子表面活性剂（Brij、Span）。除了一些例外情况，这些体系中已证明水的增溶作用有所增强。混合反胶束体系中的最大水增溶能力（ω(0,max)）出现在非离子表面活性剂的特定摩尔分数处，记为X(nonionic,max)。在这些体系中添加电解质（NaCl或NaBr），在303K下，无论是在固定的非离子表面活性剂组成（X(nonionic)；0.1）还是在X(nonionic,max)时，都倾向于进一步提高它们的增溶能力。电解质的最大增溶能力（ω(max)）在最佳电解质浓度（记为NaCl或NaBr）时获得。已发现所有这些参数，即ω(0,max)与X(nonionic,max)以及ω(max)与NaCl，都取决于表面活性剂成分（含量、EO链、极性头基的构型以及非离子表面活性剂的烃基部分）和油的类型。还研究了这些体系的电导行为，重点关注水含量（ω）、非离子表面活性剂含量（X(nonionic)）、电解质浓度（[NaCl]或[NaBr]）和油的影响。在其中一些体系中观察到了电导的渗滤现象，并通过考虑这些变量对油/水界面刚性和表面活性剂聚集体的吸引相互作用的影响来进行解释。在增溶能力与X(nonionic)或[电解质]曲线中描绘了渗滤区域，以便与水或电解质的最大增溶能力相关联。这些研究中获得的总体结果，已根据Shah及其同事提出的关于油包水微乳液中水溶解度的模型进行了解释，因为他们的模型提出，决定这些体系溶解度的两个主要效应是分隔油和水的表面活性剂膜的曲率以及水滴之间的相互作用。
