title: Understanding the structure of hydrophobic surfactants at the air/water interface from molecular level.
abstract: 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.
authors.affiliation: 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.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhipei
authors.initials: Z
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Ren
authors.forename: Pan
authors.initials: P
authors.lastname: Wu
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Shen
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Xinping
authors.initials: X
authors.lastname: Wang
mesh_terms: D000388:Air; D005466:Fluorocarbons / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D044367:Phase Transition; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D005466:Fluorocarbons; D013501:Surface-Active Agents; D014867:Water