Surface tension of a series of poly(ethylene glycol)-octyl sulfosuccinates at different temperatures was measured, and the interfacial properties were investigated in the absence and presence of inorganic salts. Surface tension results indicate that critical micelle concentration (CMC) values of five surfactants (C8-PEG200, C8-PEG400, C8-PEG600, C8-PEG800, and C8-PEG1000) decrease as the molecular weight of polyethylene glycol (PEG) segments and the experimental temperature increases. The surface activity of the C8-PEG series changes with temperature, and the surface tension at the CMC (γ_CMC) of the C8-PEG series decreases initially and then increases as the PEG molecular weight increases. This behavior may be attributed to the dehydration of the surfactant molecules, resulting in the change of hydrophile–lipophile balance for the different EO numbers in the surfactant molecules, which form a different surface energy film at the air–water interface. Negative ΔG_m indicates that the micellization process of these surfactants is spontaneous and an entropically driven process. For the water/alkane interface, these surfactants have low interfacial activity. The interfacial tension (IFT) between these surfactants and alkanes increases first and then decreases with the increase in the molecular weight of PEG segments. After the addition of salt, the interfacial activity of the investigated surfactants increases significantly. The IFT between C8-PEG800 and 10–12 alkanes and between C8-PEG1000 and 12–16 alkanes reaches a low IFT magnitude of 10⁻² mN m⁻¹ in the presence of 0.5% CaCl₂ or the mixed inorganic salts 0.5% NaCl+0.5% CaCl₂.

中文翻译：

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聚（乙二醇）-辛基磺基琥珀酸酯的热力学参数和界面性质

测量了一系列聚（乙二醇）-辛基磺基琥珀酸酯在不同温度下的表面张力，并在无机盐存在和不存在的情况下研究了界面性质。表面张力结果表明，随着聚乙二醇 (PEG) 链段的分子量和实验温度升高。C8-PEG 系列的表面活性随温度变化，CMC 处的表面张力 ( γ _CMC) 的 C8-PEG 系列最初减少，然后随着 PEG 分子量的增加而增加。这种行为可能归因于表面活性剂分子的脱水，导致表面活性剂分子中不同EO数量的亲水-亲油平衡发生变化，从而在空气-水界面形成不同的表面能膜。负 ΔG _m表明这些表面活性剂的胶束化过程是自发的和熵驱动的过程。对于水/烷烃界面，这些表面活性剂的界面活性较低。这些表面活性剂与烷烃之间的界面张力（IFT）随着PEG链段分子量的增加先增加后减小。添加盐后，所研究的表面活性剂的界面活性显着增加。C8-PEG800 与 10-12 烷烃之间以及 C8-PEG1000 与 12-16 烷烃之间的 IFT在 0.5% CaCl ₂或混合无机盐 0.5% NaCl存在下达到 10 ^-2 mN m ^-1的低 IFT 量级+0.5% CaCl ₂。