Water soluble hyperbranched polymers from controlled radical homopolymerization of PEG diacrylate†
A series of water soluble PEG based hyperbranched polymers were successfully synthesized by homopolymerization of poly(ethylene glycol) diacrylate (PEGDA) (Mn = 575 and 700 g mol−1 respectively) via vinyl oligomer combination. The homopolymerization of diacrylate macromers underwent a slow vinyl propagation combined with a polycondensation by coupling of reactive oligomers. At a high initiator-to-monomer ratio (e.g. 1 : 2), high monomer conversions up to 96% were achieved in concentrated reaction conditions (60% w/v) without gelation. The hyperbranched polymers obtained from homopolymerization of PEGDA575 show concentration-dependent thermoresponsive properties in aqueous solutions.