Preparation and Controlled Degradation of Model Amphiphilic Long-Subchain Hyperbranched Copolymers: Hyperblock versus Hypergraft

The controlled degradation of amphiphilic hyperbranched polymers (AHPs) is the first consideration for their bio-related applications. In this contribution, we aim to get some insight into the effect of block distribution and composition on the degradation behavior of AHPs model systems. Degradable amphiphilic hyperbranched block (Hyperblock) and graft (Hypergraft) copolymers with hydrophobic poly(epsilon-caprolactone) (PCL) and hydrophilic poly[tri(ethylene glycol) methyl ether acrylate] (PTEGMA) as building blocks were prepared in this study, i.e., HB-PCL-b-PTEGMA and HB-PCL-g-PTEGMA. The two kinds of AHPs own cleavable disulfide linkages embedded at all branching sites. Their degradation behavior was comparatively investigated in aqueous solutions. The results reveal that the block distribution and composition play different roles in the regulation of degradation behavior of long-subchain hyperbranched self-assembly amphiphiles(SAs). Namely, the degradation process is mainly affected by chain architecture of resultant SAs, while for a given architecture, the degradation rate can be regulated by systematically varying the block composition.