Abstract:

Two nonionic surfactants were synthesized using N-dodecylsuccinic anhydride, L-leucine, and polyether alcohol as materials. In order to study the aggregation morphology and properties of these two surfactants, their surface tension at different concentrations was tested and the critical micelle concentration (CMC) was determined based on the γ-lgc curve. The molecular dynamics simulation techniques was used to study the aggregation pattern of surfactants at the oil-water interface and the interaction with oil and water. The results showed that compared to surfactant 1,surfactant 2 had more nonionic hydrophilic components and thus reducing surface tension was more effective. The critical surface tensions (γ_CMC) of surfactant 1 and surfactant 2 were 25.54 and 24.46 mN/m. At low concentration, both of the two nonionic surfactants have high water precipitation rate and poor emulsification effect, but at high concentration, the emulsification effect is better, and the lotion prepared with two nonionic surfactants has certain stability. The electrostatic potential distribution of surfactant molecules affects their hydrophilic and oleophilic properties.

Key words: Nonionic surfactants, Surface tension, Molecular dynamics simulation

摘要：

利用N-十二烷基琥珀酸酐、L-亮氨酸和聚醚醇为原料合成了两种非离子型表面活性剂，并通过核磁共振氢谱验证了分子结构；通过表面张力仪分别测试了两种非离子型表面活性剂在不同浓度下的表面张力，并根据γ-lgc曲线确定了临界胶束浓度；通过析水率研究了表面活性剂的乳化性能；使用分子动力学模拟技术，研究了表面活性剂在油水界面处的聚集形态以及与油和水之间的作用。结果表明，与表面活性剂1相比，表面活性剂2含更多的非离子亲水组分，因此降低表面张力效果更好；表面活性剂1及表面活性剂2的临界表面张力（γ_CMC）分别为25.54、24.46 mN/m；在低浓度下，两种非离子型表面活性剂均具有较高的析水率，乳化效果不佳，但在高浓度下乳化效果较好，采用两种非离子型表面活性剂制备的乳液均具有一定的稳定性；表面活性剂分子的静电势分布影响了其亲水和亲油的性质。

关键词: 非离子型表面活性剂, 表面张力, 分子动力学模拟