D. Ruppelt et al., INFLUENCE OF CATIONIC POLYELECTROLYTES ON STRUCTURE FORMATION IN LAMELLAR LIQUID-CRYSTALLINE SYSTEMS, Langmuir, 13(13), 1997, pp. 3316-3319
The influence of cationic polyelectrolytes, poly[(diallyldimethylammon
ium chloride)-co-(N-methyl-N-vinylacetamide)] (poly(DADMAC-co-NMVA)) o
f different charge density in contract to that of a noncharged polymer
, poly(N-methyl-N-vinylacetamide) (polyNMVA), on the lamellar liquid c
rystalline system sodium dodecyl sulfate (SDS)/decanol/water was inves
tigated by means of microscopy observation between crossed polarizers,
by small angle X-ray diffraction, and by theology. The lamellar liqui
d crystal remained stable in all investigated formulations. The result
s depended on the charge density as well as the concentration of the i
ncorporated polymer. For the polymer with the highest charge two lamel
lar structures existed concurrently. In excess of a certain concentrat
ion the highest charged polymer adsorbed flat onto the SDS-decanol bil
ayer as shown by its changed interlayer spacing, whereas at lower conc
entration the polymer did not have a discernible effect on the X-ray d
iffraction pattern. The results obtained for mixtures of the lowest ch
arged polymer are in accordance with a loop adsorption of the polymer
onto the SDS-decanol bilayer. Incorporation of the noncharged polymer
did not lead to such adsorption structures and a conclusion of the imp
ortance of electrostatic interactions depending on the charge density
of the polymer is reasonable. The results obtained by SAXS measurement
s were supported by the results of rheological measurements.