Multi-responsive poly(oligo(ethylene glycol)methyl methacrylate)-co-poly(2-(diisopropylamino)ethyl methacrylate) hyperbranched copolymers via reversible addition fragmentation chain transfer polymerization

Abstract

In this work, we report on the synthesis and self-organization in aqueous media of a series of novel multi-responsive poly(oligo(ethylene glycol)methyl methacrylate)-co-poly(2-(diisopropylamino)ethyl methacrylate), P(OEGMA-co-DIPAEMA), hyperbranched copolymers, using ethylene glycol dimethacrylate (EGDMA) units as branching points. Three P(OEGMA-co-DIPAEMA) hyperbranched copolymers with different ratios of hydrophilic to hydrophobic components are prepared by the reversible addition–fragmentation chain transfer (RAFT) polymerization, in order to study their properties in aqueous solutions. By using dynamic light scattering (DLS), the formation of aggregates with dimensions in the nanoscale, responsive to changes in solution temperature and pH, is observed. The hyperbranched copolymer with the lowest DIPAEMA hydrophobic component shows the largest dimensions at pH 7 and pH 10 compared to the other two copolymers. The hyperbranched copolymers are capable of encapsulating the hydrophobic drug curcumin (CUR) and demonstrate stability in the presence of serum proteins. These new hyperbranched copolymers could be potential candidates for drug delivery and bio-imaging applications.