Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 8: Poster Session Ia
BP 8.23: Poster
Montag, 18. März 2024, 18:00–20:30, Poster C
Superstructure in lipopolymer monolayers at the air/water interface — •Issam Assi, Heiko Ahrens, and Christiane A. Helm — Institute of Physics, University of Greifswald, 17489 Greifswald, Germany
Lipopolymers with covalently bound poly(ethylene oxide) (EON)head groups have been introduced to stabilize bilayer membranes. Langmuir monolayers of the lipopolymer DSPE-EON at the air/water interface show in the isotherm a transition from the liquid expanded to the liquid condensed phase, which is confirmed by in-situ Grazing Incidence X-ray Diffraction (GID). A laterally inhomogeneous film of condensed ordered alkyl chains embedded in a matrix of solvated polymers is formed. Small Angle GID shows that these lipid domains are ordered with a lattice constant of about 12 nm. Hexagonally ordered lipid domains were observed in situ with GID, which changed on further compression to a lamellar phase (nanostripes). The films stayed homogeneous on the micrometer scale as observed with Brewster Angle Microscopy. On transferred monolayers, these supramolecular phases were observed with AFM. The enthalpy of the phase transition was determined from isotherms at different temperatures for several EO degrees of polymerization (N between 6 and 112). The lattice constants of the hexagonally ordered lipid domains and the nanodomains changed very little.
Keywords: PEG; lipid monolayer; nanostructure