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.