Two generations of novel linear‐dendritic carboxylate surfactants C₁₈‐G₁‐(COONa)₂ and C₁₈‐G₂‐(COONa)₄ have been synthesized by the divergent method and their structures are characterized by ¹H Nuclear Magnetic Resonance and Infrared analysis. The electrical conductivity measurement is used to measure the Krafft temperatures of C₁₈‐G₁‐(COONa)₂ and C₁₈‐G₂‐(COONa)₄, which are much smaller than those of the corresponding conventional surfactant sodium stearate. The markedly enhanced solubility of two linear‐dendritic surfactants is ascribed to the high hydrophilicity of surfactant headgroups induced by the carboxylate and ester groups. The critical micelle concentration (CMC) values obtained from both the electrical conductivity and surface tension measurements indicate that the micellizations of linear‐dendritic surfactants become favorable with the increase in the number of the surfactant headgroup. However, the surface activity parameters including the surface tension at the CMC, maximum surface excess, and minimum surface area reveal that C₁₈‐G₁‐(COONa)₂ exhibits greater efficiency in absorbing at the air/water interface compared to C₁₈‐G₂‐(COONa)₄, owing to their different steric repulsions of the surfactant headgroups. In addition, C₁₈‐G₁‐(COONa)₂ and C₁₈‐G₂‐(COONa)₄ have higher emulsifying ability than the conventional surfactants sodium stearate and sodium octadecyl sulfate.

中文翻译：

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新型线性树枝状羧酸盐表面活性剂的合成，胶束化和表面活性

通过发散法合成了两代新型线性树突状羧酸盐表面活性剂C ₁₈ -G _1-（COONa）₂和C ₁₈ -G _2-（COONa）₄，其结构具有¹ H核磁共振和红外光谱的特征分析。电导率测量用于测量C ₁₈ ‐G _1‐（COONa）₂和C ₁₈ ‐G _2‐（COONa）₄的Krafft温度，比相应的常规表面活性剂硬脂酸钠小得多。两种线性树突状表面活性剂的溶解度显着提高归因于羧酸根和酯基诱导的表面活性剂头基的高亲水性。从电导率和表面张力测量获得的临界胶束浓度（CMC）值表明，线性树突状表面活性剂的胶束化随着表面活性剂头基数量的增加而变得有利。但是，包括CMC处的表面张力，最大表面过量和最小表面积在内的表面活性参数表明，C ₁₈ -G _1-（COONa）₂与表面活性剂头基的空间排斥力不同，与C ₁₈ -G _2-（COONa）₄相比，在空气/水界面的吸收效率更高。另外，C ₁₈ -G _1-（COONa）₂和C ₁₈ -G _2-（COONa）₄具有比常规表面活性剂硬脂酸钠和十八烷基硫酸钠更高的乳化能力。