The aggregation phenomena of two ionic liquid surfactants—1-decyl-3-methylimidazolium chloride (C10MeImCl) and 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl) have been investigated in aqueous solutions in the presence of a polyelectrolyte, sodium polystyrenesulfonate (NaPSS), using electrical conductivity, surface tension, fluorescence and vapor pressure measurements. The counterion-condensation behavior of aqueous NaPSS has also been studied and approximately 62% of the counterions have been found to remain uncondensed in these solutions. The characteristic concentrations signifying different kinds of interactions, namely the critical aggregation concentration and the polymer saturation concentration, in the premicellar regime have been identified. Surface-active complexes with bound surfactant monomers onto the polyion backbone, non-surface active aggregates with small micellar units wrapped by polyion chains, and non-surface active micelles of ionic liquid surfactant monomers, were found to form in aqueous ionic liquid surfactant solutions in the presence of NaPSS. The surfactant concentration where polyelectrolyte–surfactant monomer complexes begin to form (cac), the concentration where the polyion chains get saturated with the small micellar units (psc), and the concentration where micelles of ionic liquid surfactant molecules begin to appear (cmc*) were identified in aqueous C16MeImCl solutions in the presence of NaPSS. Only two critical concentrations, namely the psc, and cmc* were, however, detected in aqueous C10MeImCl solutions in the presence of NaPSS. Effects of alkyl chain length of the ionic liquid surfactants, temperature, NaPSS concentration, and the charge parameter of NaPSS on the self-aggregation of the ionic liquid surfactants have been considered to elucidate the interactions in these mixed systems. The thermodynamics of micellization in these systems have also been studied and the spontaneity of the polyelectrolyte-induced micellization processes have been rationalized for the systems investigated, with the entropy terms superseding the enthalpy terms.

中文翻译：

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聚苯乙烯磺酸钠诱导离子液体表面活性剂在水溶液中的胶束化

在聚电解质聚苯乙烯磺酸钠 (NaPSS) 存在下，研究了两种离子液体表面活性剂——1-癸基-3-甲基咪唑氯化物 (C10MeImCl) 和 1-十六烷基-3-甲基咪唑氯化物 (C16MeImCl) 在水溶液中的聚集现象，使用电导率、表面张力、荧光和蒸气压测量。还研究了 NaPSS 水溶液的反离子冷凝行为，发现大约 62% 的反离子在这些溶液中保持未冷凝。已经确定了表征不同类型相互作用的特征浓度，即临界聚集浓度和聚合物饱和浓度，在预胶束状态下。表面活性复合物与结合在聚离子骨架上的表面活性剂单体，发现在存在 NaPSS 的情况下，在水性离子液体表面活性剂溶液中形成了由聚离子链包裹的具有小胶束单元的非表面活性聚集体，以及离子液体表面活性剂单体的非表面活性胶束。聚电解质-表面活性剂单体复合物开始形成的表面活性剂浓度 (cac)，聚离子链被小胶束单元饱和的浓度 (psc)，以及离子液体表面活性剂分子的胶束开始出现的浓度 (cmc*)在 NaPSS 存在下，在 C16MeImCl 水溶液中进行鉴定。然而，在存在 NaPSS 的 C10MeImCl 水溶液中仅检测到两个临界浓度，即 psc 和 cmc*。离子液体表面活性剂烷基链长、温度、NaPSS浓度、NaPSS 对离子液体表面活性剂自聚集的电荷参数被认为可以阐明这些混合体系中的相互作用。还研究了这些系统中胶束化的热力学，并对所研究的系统合理化了聚电解质诱导的胶束化过程的自发性，熵项取代了焓项。