RAFT mediated one-pot synthesis of glycopolymer particles with tunable core–shell morphology

Abstract

Here we report a simple and one-pot method for the synthesis of glycopolymer based colloidal particles with tunable core–shell morphology using reversible addition fragmentation chain transfer (RAFT) polymerization. A hydrophilic carbohydrate functionalized monomer (called glycomonomer) namely allyl-α-D-glucopyranoside (α-Glu) was polymerized with the RAFT agent to yield a macro-sugar chain, which acts as a macro-RAFT agent, and then this chain was further extended by copolymerizing the hydrophobic styrene monomer. The resulting polymer chains consist of polystyrene (PS) as a hydrophobic chain and glycopolymer (GP) as a hydrophilic chain. Several microscopic techniques which include FE-SEM, TEM, AFM and confocal Raman imaging proved the formation of core–shell colloidal particle morphology of the synthesized PS–GP in which PS was found in the core of the particle and the shell was made up of GP. The tunability in the particle size and in the core (PS)–shell (GP) dimension was achieved by altering the macro-sugar chain length and hydrophilic monomer (sugar) concentration in the polymerization feed. The formation of more number of macro-sugar chains with the increasing sugar content in the feed led to the production of a large number of smaller sized micelles in the polymerization medium which yielded smaller size particles. The colloidal stability and the molecular weight of the resulting PS–GP core–shell nanoparticles were found to be dependent upon both macro-RAFT and sugar content in the reaction feed.