Water-Soluble and Clickable Segmented Hyperbranched Polymers for Multifunctionalization and Novel Architecture Construction

A series of novel and narrowly polydispersed regular chain-segmented hyperbranched poly(tertiary amino methacrylate)s (HPTAM)s with hydrophilic core and hydrophobic shell were synthesized via the combination of self-condensing vinyl copolymerization (SCVCP) and reversible addition fragmentation chain transfer (RAFT) methodology. 2-(Dimethylamino)ethyl methacrylate (DMAEMA) and 24(2(((dodecylthio)carbonothioyl)thio)-2-methylpropanoyl)oxy)- ethyl acrylate (ACDT) at various molar feed ratios (gamma, [DMAEMA]:[ACDT]) were chosen as monomers for linear segment formation of the structure. The copolymerization kinetics revealed that during the polymerization the real-time gamma value kept almost constant and was consistent with the initial feed ratio. So HPTAMs possesses regular linear chains between every two neighboring branching units, which closely resemble HyperMacs in structure. Fast click-like Menschutkin reaction (i.e., quaternarization) of the segmented hyperbranched polymers with propargyl bromide and 2-azidoethyl 2-bromoacetate readily afforded water-soluble and clickable poly(propargyl quaternary ammonium methacrylate) (HPPrAM) and poly(azide quaternary ammonium methacrylate) (HPAzAM), respectively. Through Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), the HPPrAMs were functionalized with 1-azidododecane and 2-azidoethyl 2-bromoisobutyrate, giving birth to amphiphilic hyperbranched polyelectrolytes (or hyperbranched surfactants) and hyperbranched ATRP macroinitiators, respectively. The HPAzAMs were efficiently decorated with monoalkynyl poly(ethylene glycol) (PEG-Alk) via CuAAC, generating dendritic polymer brushes, a novel architecture reported for the first time. In addition, core-functionazlied star-shaped HPPrAM-star-poly(tert-butyl acrylate) was synthesized by RAFT copolymerization and Menschutkin reaction.