The thickening behaviors in aqueous solution of mixed surfactant mixtures containing an amino acid-based surfactant, sodium lauroyl sarcosinate (SLSar), and a nonionic surfactant, N-dodecylpyrrolidone (C12P) were investigated using the rheological methods of steady-shear and frequency sweep. The results varying the added C12P concentration and the mass ratio of SLSar and C12P indicate that the addition of C12P can promote the formation of wormlike micelles and hydrogels, resulting in viscosity enhancement in the mixed aqueous solution of SLSar and C12P. Viscosity maxima in SLSar/water/C12P systems are sensitive to pH, temperature, the concentration of added C12P, and the mass ratio of SLSar and C12P. In the high concentration of total surfactant (30–39 wt%), the enhancement of viscosity obviously occurs by adding 6 wt% C12P, whereas in the low concentration of total surfactant (15 wt%), the C12P must be added more than 9 wt% in 15 wt% mixtures of SLSar and C12P. Moreover, during the solution pH lowered from SLSar' natural pH of 7.2 to the mixture's pKa 5.2, the intermolecular forces between SLSar acid, SLSar anionic salt, and C12P gradually reduce the overall headgroups areas and contribute to the formation of wormlike micelles, hydrogels, and the thickening behaviors.

中文翻译：

---

烷基吡咯烷酮对氨基酸类表面活性剂的水溶液增稠

使用稳定剪切和频率扫描的流变学方法研究了混合表面活性剂混合物在水溶液中的增稠行为，该混合物含有基于氨基酸的表面活性剂月桂酰肌氨酸钠 (SLSar) 和非离子表面活性剂 N-十二烷基吡咯烷酮 (C12P)。改变C12P浓度和SLSar与C12P质量比的结果表明，C12P的加入可以促进蠕虫状胶束和水凝胶的形成，从而提高SLSar和C12P混合水溶液的粘度。SLSar/水/C12P 系统的粘度最大值对 pH 值、温度、添加的 C12P 的浓度以及 SLSar 和 C12P 的质量比敏感。在总表面活性剂的高浓度（30-39 wt%）中，添加 6 wt% C12P 明显提高了粘度，而在低浓度的总表面活性剂 (15 wt%) 中，C12P 必须在 15 wt% 的 SLSar 和 C12P 混合物中添加超过 9 wt%。此外，在溶液 pH 值从 SLSar 的自然 pH 值 7.2 降低到混合物的 pKa 5.2 期间，SLSar 酸、SLSar 阴离子盐和 C12P 之间的分子间作用力逐渐减少了总的头基区域并有助于形成蠕虫状胶束、水凝胶、和增厚行为。