Lipid Monolayers with Adsorbed Oppositely Charged Polyelectrolytes: Influence of Reduced Charge Densities

Polymers

Thomas Ortmann²  Heiko Ahrens²  Sven Milewski²  Frank Lawrenz²  Andreas Gröning²  André Laschewsky³  Sebastien Garnier¹ 

[1] Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam-Golm, Germany; E-Mail:;Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Straße 6, D-17487 Greifswald, Germany; E-Mails:;Fraunhofer Institute for Applied Polymer Research, Geiselberg Str. 67, D-14476 Potsdam-Golm, Germany; E-Mail:

关键词: lipid monolayer;    polyelectrolyte adsorption;    statistical copolymer;    two-dimensional phases;    surface charge;    nematic phase;    grazing incidence X-ray diffraction;   

DOI  :  10.3390/polym6071999

来源: mdpi

【 摘 要 】

Polyelectrolytes in dilute solutions (0.01 mmol/L) adsorb in a two-dimensional lamellar phase to oppositely charged lipid monolayers at the air/water interface. The interchain separation is monitored by Grazing Incidence X-ray Diffraction. On monolayer compression, the interchain separation decreases to a factor of two. To investigate the influence of the electrostatic interaction, either the line charge density of the polymer is reduced (a statistic copolymer with 90% and 50% charged monomers) or mixtures between charged and uncharged lipids are used (dipalmitoylphosphatidylcholine (DPPC)/dioctadecyldimethylammonium bromide (DODAB)) On decrease of the surface charge density, the interchain separation increases, while on decrease of the linear charge density, the interchain separation decreases. The ratio between charged monomers and charged lipid molecules is fairly constant; it decreases up to 30% when the lipids are in the fluid phase. With decreasing surface charge or linear charge density, the correlation length of the lamellar order decreases.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.