Methanol–water system possesses unusual interactions, which may affect surfactant self-assembly. The main objective of this study was to investigate the interactions and aggregation behavior of ionic surfactants sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) and their equimolar catanionic binary mixtures (CAM) and their ternary mixtures with poly(ethylene oxide) (PEO) in aqueous solutions containing different volume percentages of methanol. Conductometry, surface tensiometry, and dynamic light scattering were employed for this purpose. The aggregation in all the systems showed methanol-dependent patterns. The maximum shifts observed in the critical aggregation concentrations were 5.5, 2.7, 6.3, 4.1, and 4.4 mM, respectively, for SDS, CTAB, CAM, SDS/PEO, and CTAB/PEO systems for variation in MeOH from 5% to 30% v/v. The change in dielectric of the media and chaotropic nature of methanol was responsible for alteration in self-assembly. The nature of surfactant especially and head group hydrophobicity also played a significant role in the process. The maximum change in area per molecule (i.e., ~4 nm²) occurred for CTAB/PEO system. The aggregation was delayed in surfactant solutions; however, the presence of polymer induced aggregation due to favorable polymer–surfactant interactions involving the surfactant adsorption onto polymer chains and formation of mixed aggregates. The hydrodynamic radii for CTAB/PEO systems, which were nearly 10 times greater than those recorded for SDS/PEO, showed the transition of system to nonspherical aggregated states. In short, the presence of methanol retarded the aggregation in surfactant and surfactant–polymer systems.

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甲醇对表面活性剂和表面活性剂-PEO 混合物的影响

甲醇-水体系具有不寻常的相互作用，这可能会影响表面活性剂的自组装。本研究的主要目的是研究离子表面活性剂十二烷基硫酸钠 (SDS) 和十六烷基三甲基溴化铵 (CTAB) 及其等摩尔阳离子二元混合物 (CAM) 及其与聚环氧乙烷 (PEO) 的三元混合物的相互作用和聚集行为。 ) 在含有不同体积百分比的甲醇的水溶液中。为此目的采用电导测定法、表面张力测定法和动态光散射法。所有系统中的聚集都显示出依赖甲醇的模式。对于 SDS、CTAB、CAM、SDS/PEO 和 CTAB/PEO 系统，临界聚集浓度的最大变化分别为 5.5、2.7、6.3、4.1 和 4.4 mM，MeOH 从 5% 到 30% 的变化体积/体积。介质电介质的变化和甲醇的离液性质是导致自组装改变的原因。特别是表面活性剂的性质和头基疏水性也在该过程中发挥了重要作用。每个分子的最大面积变化（即~4 nm² ) 发生在 CTAB/PEO 系统中。在表面活性剂溶液中聚集延迟；然而，由于有利的聚合物-表面活性剂相互作用，包括表面活性剂吸附到聚合物链上并形成混合聚集体，聚合物的存在会引起聚集。CTAB/PEO 系统的流体动力学半径比 SDS/PEO 记录的流体动力学半径大近 10 倍，表明系统向非球形聚集态的转变。简而言之，甲醇的存在延缓了表面活性剂和表面活性剂-聚合物体系中的聚集。