Self-assembling amphiphilic polyelectrolytes and their nanostructures

The self-assembling behavior of random copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate (AMPS) and hydrophobic comonomers possessing dodecyl groups linked by various spacer bonds was discussed with a focus on the effect of the spacer. The characterization of association behavior of such polymers in water using quasielastic light scattering, capillary electrophoresis, NMR relaxation, various fluorescence, and viscoelastic methods was described. These copolymers form a variety of self-assembled nanostructures depending on the type of the spacer. Random copolymers of AMPS acid N-dodecylmethacrylamide show a strong preference for intrapolymer self-association even in concentrated aqueous solutions forming single-macrornolecular self-assemblies (unimolecular micelles). In contrast, random copolymers of AMPS and dodecyl methacrylate are prone to undergo interpolymer associations yielding multipolymer micelles. In random copolymers of AMPS and a methacrylate substituted a nonionic surfactant (HO(CH(2)CH(2)O)(25)C(12)H(25)) (C(12)E(25)), dodecyl groups are much less restricted by the polymer backbone because they are linked via a long, flexible hydrophilic spacer. Thus, the polymer-bound C(12)E(25) surfactant moieties form micelles similar to those formed by discrete surfactants, but they are bridged by polymer chains forming a network structure.