采用分子动力学模拟方法研究了双链阴离子表面活性剂1—烷基-癸基磺酸钠(1-Cm-C9-SO3Na)在气/液界面的聚集行为.通过分析体系中各组分的密度分布和径向分布函数,考察了m大小对其界面性质的影响.结果表明:随着m的增大,表面活性剂的疏水性增强,疏水碳链的倾斜角也随之降低;m=4时,1-C4-C9-SO3Na分子采用平躺的方式在界面上聚集,S-Na+和S-S的相互作用最大,极性头基的水化能力最弱.通过模拟和实验对比得出,m增加到4个时,对该类双链阴离子表面活性剂性能的提高最显著.%The aggregation behavior of the double-chained anionic surfactant 1-alkyl-decyl sodium sulfonate (1-Cnm-C9-SO3-Na) at the air/liquid interface was investigated using molecular dynamics simulation.The influences of the m value on the interfacial properties of the surfactant were compared using density profile and radial distribution function (RDF).The results showed that the hydrophobic ability of the surfactant increase and the slant angles of hydrophobic carbon chains decrease with increasing m.For m =4,the 1-C4-C9-SO3Na form aggregates by lying on the interface;the S-S and S-Na+ interactions are the highest for m =4 among all systems studied,while the hydration ability of its polar head is the weakest.The simulation and experimental results show that the interfacial performance is the best for 1-C4-C9-SO3Na.
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