Zhang Li, Liu Zhipei, Ren Tao, Wu Pan, Shen Jia-Wei, Zhang Wei, Wang Xinping
Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University , Xiasha Higher Education Zone, Hangzhou, Zhejiang 310018, People's Republic of China.
Langmuir. 2014 Nov 25;30(46):13815-22. doi: 10.1021/la5030586. Epub 2014 Nov 14.
Understanding the behavior of fluorocarbon surfactants at the air/water interface is crucial for many applications, such as lubricants, paints, cosmetics, and fire-fighting foams. In this study, molecular dynamics (MD) simulations were employed to investigate the microscopic properties of non-ionic fluorocarbon surfactants at the air/water interface. Several properties, including the distribution of head groups, the distribution probability of the tilt angle between hydrophobic tails with respect to the xy plane, and the order parameter of surfactants, were computed to probe the structure of hydrophobic surfactants at the air/water interface. The effects of the monomer structure on interfacial phenomena of non-ionic surfactants were investigated as well. It is observed that the structure of fluorocarbon surfactants at the air/water interface is more ordered than that of hydrocarbons, which is dominated by the van der Waals interaction between surfactants and water molecules. However, replacing one or two CF2 with one or two CH2 group does not significantly influence the interfacial structure, suggesting that hydrocarbons may be promising alternatives to perfluorinated surfactants.
了解氟碳表面活性剂在空气/水界面的行为对于许多应用至关重要，如润滑剂、涂料、化妆品和消防泡沫。在本研究中，采用分子动力学（MD）模拟来研究非离子氟碳表面活性剂在空气/水界面的微观性质。计算了包括头基分布、疏水尾相对于xy平面的倾斜角分布概率以及表面活性剂的序参量等几个性质，以探究疏水表面活性剂在空气/水界面的结构。还研究了单体结构对非离子表面活性剂界面现象的影响。观察到氟碳表面活性剂在空气/水界面的结构比碳氢化合物更有序，这主要由表面活性剂与水分子之间的范德华相互作用主导。然而，用一个或两个CH2基团取代一个或两个CF2不会显著影响界面结构，这表明碳氢化合物可能是全氟表面活性剂的有前途的替代品。
