Degradable Polymer Brushes Prepared via Surface-Initiated Controlled Radical Polymerization

Abstract

Hydrolytically degradable polymer brushes would represent an interesting platform for the development of functional coatings for various biomaterials applications. In this manuscript, the surface-initiated atom transfer radical copolymerization of 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) and poly(ethylene glycol) methacrylate (PEGMA) has been investigated to prepare degradable polymer brushes. The copolymerization of BMDO and PEGMA results in brushes that contain hydrolytically labile ester linkages in the polymer backbone. The thickness of these polymer brushes can be controlled via the polymerization time and the BMDO content by adjusting the monomer feed composition. The degradation of the brushes was investigated by ellipsometry and atomic force microscopy (AFM) experiments. While the brushes were relatively stable under neutral and mild-basic conditions (pH 9), degradation was significantly enhanced under acidic conditions. Degradation was found to be accelerated at low pH values (pH 3−5) and with increasing BMDO content.