| Abstract: | Small‐angle X‐ray scattering was used to investigate the nanostructures of complexes formed by slightly crosslinked anionic copolymer gels of poly(sodium methacrylate‐co‐N‐isopropylacrylamide) P(MAA/NIPAM)] with cetyltrimethylammonium bromide (CTAB), and didodecyldimethylammonium bromide (DDAB), respectively, at room temperature (～ 23°C). Several highly ordered supramolecular structures were observed in the polyelectrolyte gel–surfactant complexes. In P(MAA/NIPAM)–CTA systems, in sequence with decreasing charge density of the P(MAA/NIPAM) copolymer chains, structures of the Pm3n space group cubic, face‐centered cubic close packing of spheres, and hexagonal close packing of spheres were determined at a charge content of ≥ 75, 67, and 50%, respectively. The spheres and rods in these structures were the spherical and cylindrical micelles formed by the self‐assembly of CTA cations with their paraffin chains inside. Both the aggregation number and the size of the micelles decreased with a decreasing charge density of the copolymer chains. In the P(MAA/NIPAM)–DDA systems, the bilayer lamellar structures formed at charge contents ≥ 75% transferred to bicontinuous cubic structures of the Ia3d space group at charge contents of 50–67%. The rods in the Ia3d cubic structures were formed by the self‐assembly of double‐tailed DDA cations with polar moieties inside. The formation of these highly ordered structures were driven by both electrostatic and hydrophobic interactions of the charged copolymer chains/surfactants and the surfactants/surfactants inside the charged gels. The structures became less ordered by further decreasing the charge content of the P(MAA/NIPAM) chains. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2165–2172, 1999 |
