title: Unconventional air-stable interdigitated bilayer formed by 2,3-disubstituted fatty acid methyl esters.
abstract: A single-chain fatty acid methyl ester, racemic anti-3-fluoro-2-hydroxyeicosanoic acid methyl ester (beta-FHE), forms an unconventional air-stable interdigitated bilayer at the air-water interface. The interdigitated bilayer transferred onto solid substrate by the Langmuir-Blodgett (LB) technique keeps air-stable without any substrate modification or protein inclusion. There are two visible plateaus in the surface pressure-molecular area (pi-A) isotherms of beta-FHE Langmuir film during continuous compression. According to Brewster angle microscopy (BAM), grazing incidence X-ray diffraction (GIXD), X-ray reflectivity (XR), fluorescence microscopy (FM), and atomic force microscopy (AFM) measurements, the first plateau is attributed to the coexistence of liquid expanded (LE) and liquid condensed (LC) phases in the monolayer, while the second plateau is interpreted as the transition from LC monolayer to interdigitated bilayer. The coupling between tilt and curvature associated with the packing mismatch between headgroup and chain gives rise to buckling and folding of the monolayer, leading to the transition of the LC monolayer to a bilayer structure. The diffusion-limited aggregation (DLA) model is applied to describe the formation of the fractal structures of the bilayer as observed in the second plateau. In addition, the transition between monolayer and bilayer is reversible. The present works are interesting for understanding biological processes, for example, the behavior of lung surfactants.
authors.affiliation: Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Chen
authors.forename: Susanne
authors.initials: S
authors.lastname: Wiehle
authors.forename: Markus
authors.initials: M
authors.lastname: Weygand
authors.forename: Gerald
authors.initials: G
authors.lastname: Brezesinski
authors.forename: Ute
authors.initials: U
authors.lastname: Klenz
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Galla
authors.forename: Harald
authors.initials: H
authors.lastname: Fuchs
authors.forename: Günter
authors.initials: G
authors.lastname: Haufe
authors.forename: Lifeng
authors.initials: L
authors.lastname: Chi
mesh_terms: D000388:Air; D004952:Esters / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry*; D007202:Indicators and Reagents; D008051:Lipid Bilayers / Q000737:chemistry*; D008168:Lung / Q000737:chemistry; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D011312:Pressure; D017550:Spectroscopy, Fourier Transform Infrared; D013501:Surface-Active Agents / Q000737:chemistry; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D004952:Esters; D005227:Fatty Acids; D007202:Indicators and Reagents; D008051:Lipid Bilayers; D013501:Surface-Active Agents