Facile synthesis of monocyclic, dumbbell-shaped and jellyfish-like copolymers using a telechelic multisite hexablock copolymer

Abstract

The combination of cyclic and comblike blocks in architectural polymers can provide insight into topology-dependent physical properties. Despite tremendous progress, jellyfish-like polymers (JFPs) with a macrocycle-bearing backbone have been scarcely reported. To enrich the family of JFPs, a telechelic multisite hexablock copolymer comprising alternating sequences of poly(styrene-co-maleimide) and polystyrene blocks and diverse functionalities of thiolactone, hydroxyl and bromine is designed. The first intrachain folding affords a cyclic copolymer, followed by the second intracyclic folding via a thio-bromo click reaction to achieve a dumbbell-shaped copolymer. The subsequent graft reactions and hydrolysis afford homografted and heterografted JFPs comprising poly(ε-caprolactone), poly(ethylene glycol), poly(tert-butyl acrylate) and/or poly(acrylic acid) segments. Depending on the topology, composition and solution pH, distinct nano-objects including spheres, vesicles, cylinders, spindles and lamellae are fabricated by self-assembly. Rational design of multisite multiblock copolymers holds great promise in the construction of novel JFPs comprising macrocycle- and folding block-bearing backbones.