TY  - JOUR
A1  - Ortmann, Thomas
A1  - Ahrens, Heiko
A1  - Milewski, Sven
A1  - Lawrenz, Frank
A1  - Groening, Andreas
A1  - Laschewsky, André
A1  - Garnier, Sebastien
A1  - Helm, Christiane A.
T1  - Lipid monolayers with adsorbed oppositely charged polyelectrolytes: Influence of reduced charge densities
JF  - Polymers
N2  - 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.
KW  - lipid monolayer
KW  - polyelectrolyte adsorption
KW  - statistical copolymer
KW  - two-dimensional phases
KW  - surface charge
KW  - nematic phase
KW  - grazing incidence X-ray diffraction
Y1  - 2014
U6  - https://doi.org/10.3390/polym6071999
SN  - 2073-4360
VL  - 6
IS  - 7
SP  - 1999
EP  - 2017
PB  - MDPI
CY  - Basel
ER  -