INFLUENCE OF CATIONIC POLYELECTROLYTES ON STRUCTURE FORMATION IN LAMELLAR LIQUID-CRYSTALLINE SYSTEMS

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.