Facile synthesis and self-assembly of multihetero-arm hyperbranched polymer brushes

Abstract

A facile methodology was presented for scalable synthesis of hyperbranched-star polymers with tens of hydrophilic and hydrophobic hetero-arms, in merely two steps starting from monomers. Self-condensing atom transfer radical polymerization (SC-ATRP) of a clickable initiator-monomer (click-inimer), 3-azido-2-(2-bromo-2-methylpropanoyloxy)propyl methacrylate, resulted in a hyperbranched polymer with azido and bromo multihetero-groups. Subsequently orthogonal one-pot “grafting onto” azide-alkyne click coupling and “grafting from” ATRP with the core of hyperbranched polymer afforded targeted miktoarm globular binary brushes. The brushes could readily assemble into superstructures of 150–300 nm spheres and micro-scale sheets. Furthermore, hyperbranched copolymer possessing azido, hydroxyl and bromo trihetero-groups were synthesized by self-condensing atom transfer radical copolymerization of the click-inimer and 2-hydroxyethyl methacrylate (HEMA). Hyperbranched trinity brushes were then facilely prepared via a one-pot multigrafting strategy by a combination of click chemistry, esterification, and ATRP. The trinity brushes could assemble into superstructures of micron-scale dendritic tubes.