Redox-Responsive Self-Assembly of Amphiphilic Multiblock Rod-Coil Polymers

We report redox-responsive aggregation-disaggregation behaviors of a multiblock rod-coil polymer synthesized via a cohdensation of diaminoheptaaniline and bis-succinimidyl ester terminated oligoethylene glycol. The emeraldine base state of these multiblock polymers formed spherical nanoparticles in water, whereas the aggregates disassembled upon being reduced to the leucoemer-aldine base state. The redox-responsiveness was accounted for by the formation of a compound micelle consisting of three-dimensionally interconnected, smaller puck-shaped rod-coil micellar aggregates. The rodlike heptaaniline blocks in the emeraldine base state packed parallel to each other and compactly via intermolecular hydrogen bonding to form the puck-shaped aggregates, which were bridged by oligoethylene glycol coils emanating from their two faces. It was demonstrated that the oxidized state of the rod-coil network within the compound micelles could entrap guest molecules, and reducing this network could release them. The rod-coil compound micelles with longer boil bridges exhibited a greater extent of entrapment and a higher loading efficiency.