College of Chemistry and Chemical Engineering, Northeast Petroleum University, Daqing 163318, China.
Key Laboratory of Oilfield Chemicals, China National Petroleum Corporation, Beijing 100083, China.
Molecules. 2024 Sep 10;29(18):4286. doi: 10.3390/molecules29184286.
In this paper, a series of tetrameric surfactants (4CSAZs, = 12, 14, 16) endowed with zwitterionic characteristic were synthesized by a simple and convenient method and their structures were characterized by FT-IR, H NMR and elemental analysis. Their physicochemical properties were studied using the Wilhelmy plate method, fluorescence spectra and dynamic light scattering technique. 4CSAZs have higher surface activities and tend to adsorb at the air/water surface rather than self-assembling in aqueous solution. The thermodynamic parameters obtained from surface tension measurements show that both processes of adsorption and micellization of 4CSAZs are spontaneous and that the micellization processes of 4CSAZs are entropy-driven processes. Both adsorption and micellization of 4CSAZs are inclined to occur with the increase of alkyl chain length or temperature. For 4CSAZs, there are only small-size aggregates (micelles), while the large aggregates (vesicles) are observed at the alkyl length of 4CSAZs of 14 or 16. This shows that the alkyl chain length for oligomeric surfactants has a greater sensitivity for aggregate growth. The aggregate morphologies obtained from the calculated values of critical packing parameter () for 4CSAZs and 4CSAZs can be supported by the DLS measurement results. The test results obtained by the separation-water-time method show that 4CSAZs have good emulsification performance and that the prepared emulsions appear to exit in the form of multiple emulsions. In addition, 4CSAZs have good antibacterial activities against () and Staphylococcus aureus (). The present study reveals the unique behavior of a zwitterionic tetrameric surfactant and may give new insights into molecular design and synthesis of a high degree of surfactants with different structure characteristics for potential application in various industrial fields.
本文采用简便的方法合成了一系列具有两性离子特征的四聚体表面活性剂（4CSAZs， = 12、14、16），并通过傅里叶变换红外光谱（FT-IR）、核磁共振谱（H NMR）和元素分析对其结构进行了表征。利用吊片法、荧光光谱和动态光散射技术研究了它们的物理化学性质。4CSAZs 具有较高的表面活性，倾向于在空气/水界面上吸附，而不是在水溶液中自组装。从表面张力测量得到的热力学参数表明，4CSAZs 的吸附和胶束化过程都是自发的，并且 4CSAZs 的胶束化过程是熵驱动的过程。4CSAZs 的吸附和胶束化都随着烷基链长度或温度的增加而倾向于发生。对于 4CSAZs，只有小尺寸的聚集物（胶束），而在 4CSAZs 的烷基长度为 14 或 16 时观察到大尺寸的聚集物（囊泡）。这表明低聚表面活性剂的烷基链长度对聚集物的生长具有更大的敏感性。从计算得到的临界堆积参数（）的值可以看出 4CSAZs 和 4CSAZs 的聚集形态，这可以得到 DLS 测量结果的支持。通过分离-水-时间法得到的测试结果表明，4CSAZs 具有良好的乳化性能，所制备的乳液似乎以复乳的形式存在。此外，4CSAZs 对（）和金黄色葡萄球菌（）具有良好的抗菌活性。本研究揭示了两性离子四聚体表面活性剂的独特行为，可能为具有不同结构特征的高度表面活性剂的分子设计和合成提供新的思路，有望在各个工业领域得到应用。
