title: A Langmuir and AFM study on interfacial behavior of binary monolayer of hexadecanol/DPPE at the air-water interface.
abstract: Hexadecanol is chemically stable and can be used as an effective addition in synthetic clinical lung surfactant preparations to improve their spreading properties. In this work, a detailed thermodynamic and structural characterization of a simple model system, which based on a hexadecanol-phospholipid mixture is reported. Langmuir monolayers of binary mixtures of hexadecanol/1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) have been studied with thermodynamic parameters and monolayer structure. The extent of the thermodynamic parameters has been evaluated by the direct related parameters, such as mean molecular area, percent of condensation, surface excess Gibbs free energies, isothermal compressibility, interaction energy parameter, activity coefficient and two-dimensional phase diagram. Monolayer film structure has been characterized by atomic force microscopy (AFM) technique. Combining thermodynamic and AFM data indicate that there exist repulsive and attractive interactions between the two film forming molecules and the binary films behave as non-ideal mixtures, which can be portrayed by the mole fraction of hexadecanol. At low mole fraction of hexadecanol, the monolayer is phase-separated and the interactions between hexadecanol and DPPE is more repulsive; while the content of hexadecanol up to 0.6, the monolayer becomes miscible and stable, the interaction between different molecules is more attractive. The addition of hexadecanol in the DPPE monolayer clearly affects the lateral organization of membranes and improves its surface tension kinetics. The results discussed in this context will be expected to be potential contribution for exogenous lung surfactant researches.
authors: College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China; College of Science, Xi'an University of Science and Technology, Xi'an 710054, China.
authors: Huaze
authors: H
authors: Zhu
authors: College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China. Electronic address: sunrunguang@snnu.edu.cn.
authors: Runguang
authors: R
authors: Sun
authors: College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China.
authors: Changchun
authors: C
authors: Hao
authors: College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China; College of Science, Xi'an University of Science and Technology, Xi'an 710054, China.
authors: Pengli
authors: P
authors: Zhang
mesh_terms: D005233:Fatty Alcohols / Q000737:chemistry*; D007700:Kinetics; D018625:Microscopy, Atomic Force; D044367:Phase Transition; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D013499:Surface Properties; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D005233:Fatty Alcohols; D010714:Phosphatidylethanolamines; D013501:Surface-Active Agents; D014867:Water; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; C005031:cetyl alcohol
keywords: Atomic force microscopy; Interaction; Lung surfactant; Miscibility; Monolayer