Synthesis of stimuli-sensitive copolymers by RAFT polymerization: potential candidates as drug delivery systems

Abstract

Poly(2-(dimethylamino)ethylmethacrylate-b-methymethacrylate) (PDMAEMA-b-PMMA) poly(2-(dimethylamino)ethylmethacrylate-b-vinylcaprolactam-b-(2-(dimethylamino)ethyl methacrylate) (PDMAEMA-b-PVCL-b-PDMAEMA) and poly(vinylcaprolactam-b-(2-(dimethylamino)ethylmethacrylate-b-vinylcaprolactam) (PVCL-b-PDMAEMA-b-PVCL) block copolymers were obtained by reversible addition-fragmentation chain transfer (RAFT) polymerization, and the effect of the solution pH on the particle size was investigated. In the case of PDMAEMA-b-PMMA, PDMAEMA was first synthesized using 2-cyanoprop-2-yl dithiobenzoate (CPDB) as a chain transfer agent (CTA), which was subsequently used for the RAFT polymerization of MMA. The triblock copolymers were obtained using PDMAEMA or PVCL as macro-CTAs prepared using dibenzyl trithiocarbonate (DBTTC) as a bifunctional RAFT agent. The structure and formation of the copolymers was confirmed through ¹H NMR and SEC analysis. The particle size varied considerably depending on the pH of the aqueous solutions of copolymers indicating that these materials could be potential candidates for biomedical applications.