Li Ying, Zhang Peng, Dong Feng-Lan, Cao Xu-Long, Song Xin-Wang, Cui Xiao-Hong
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
J Colloid Interface Sci. 2005 Oct 1;290(1):275-80. doi: 10.1016/j.jcis.2005.04.035.
There is a close correlation between the interfacial activity and the adsorption of the surfactant at the interface, but the detailed molecular standard information was scarce. The interfacial activity of two traditional anionic surfactants sodium dodecyl benzene sulfonate (SDBS) and sodium oleate (OAS) were studied by experimental and computer simulation methods. With the spinning drop method and the suspension drop method, the interfacial tension of oil/aqueous surfactant systems was measured, and the influence of surfactant concentration and salinity on the interfacial tension was investigated. The dissipative particle dynamics (DPD) method was used to simulate the adsorption of SDBS and OAS at the oil/water interface. It was shown that it is beneficial to decrease interfacial tension if the hydrophobic chains of the surfactant and the oil have similar structure. The accession of inorganic salts causes surfactant molecules to form more compact and ordered arrangements and helps to decrease the interfacial tension. There is an osculation relation between interfacial density and interfacial activity. The interfacial density calculated by molecular simulation is an effective parameter to exhibit the interfacial activity.
界面活性与表面活性剂在界面处的吸附之间存在密切关联，但详细的分子标准信息却很匮乏。通过实验和计算机模拟方法研究了两种传统阴离子表面活性剂十二烷基苯磺酸钠（SDBS）和油酸钠（OAS）的界面活性。采用旋滴法和悬滴法测量了油/表面活性剂水溶液体系的界面张力，并研究了表面活性剂浓度和盐度对界面张力的影响。利用耗散粒子动力学（DPD）方法模拟了SDBS和OAS在油/水界面的吸附。结果表明，如果表面活性剂的疏水链与油具有相似结构，则有利于降低界面张力。无机盐的加入会使表面活性剂分子形成更紧密、有序的排列，并有助于降低界面张力。界面密度与界面活性之间存在密切关系。通过分子模拟计算得到的界面密度是表征界面活性的一个有效参数。
