Functionalization of polymer coated surfaces by radical-exchange reactions

Abstract

The synthesis of functional polymeric coatings has gained great interest for various research area especially biosensor applications. In this thesis, novel method to make end group modifications of polymer brushes on silicon surfaces is disclosed. As an application, the aim is to design polymeric coatings with dendritic structures as a multivalent ligand display to increase binding affinity of protein during biomolecular recognition. This thesis explores the initial step of end group modification using a radical exchange reaction. In particular, di(ethylene glycol) methyl ether methacrylate based hydrophilic polymer brushes were synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) with ‘grafting from’ approach. Removal of dithio benzoate group of RAFT chain transfer agent and functionalization of polymer brush end groups were achieved via radical cross coupling reaction. Polymer brushes were treated with diazo-based derivatives containing clickable azide groups. These were modified using an alkyne containing fluorescent dye. First and second generation of polyester dendrons containing diazo groups at the core were synthesized and used for polymer chain end functionalization.