RAFT polymerization and Thiol end capped polymer

What is it about?

Some synthetic strategies including coupling reactions (e.g. ‘click’ chemistry), reversible deactivation radical polymerization (RDRP; otherwise known as controlled or ‘living’ radical polymerization), ring-opening polymerization (ROP) and group transfer polymerization have been applied for the synthesis of ABC triblock copolymers. Among these, RDRP has been demonstrated as an efficient and powerful technique for precise construction of ABC triblock copolymers. This polymerization technique can be divided into three main categories: reversible addition–fragmentation chain transfer (RAFT) polymerization, nitroxide-mediated polymerization and atom transfer radical polymerization. In this context, the RAFT technique is especially interesting, mainly due to its applicability to all types of vinyl monomers, simple reaction conditions and its potential for synthesis of homopolymers, block copolymers and post-modified polymers with controlled molecular weight, narrow dispersity and complex macromolecular architectures. Another advantage of this technique over atom transfer radical polymerization is that there are no metal contaminants in the resultant polymer, because this method is based on all-organic components. In addition, the macromolecules synthesized using the RAFT polymerization technique can be converted to thiol-end-capped polymers through chemical reduction reactions. These types of functional polymers have been used for the derivatization of interfaces with synthetic and biological molecules for tissue engineering, protein arrays, molecular diagnostics and drug delivery. Also, the strong affinity of the thiol group towards metal substrates (e.g. gold and silver) and its ability to selectively and quantitatively react with some moieties (e.g. maleimide) under physiological conditions have led to its extensive use in numerous fields.

Featured Image

Why is it important?

due to the strong affinity of the end-cap thiol group towards metal substrates (e.g. gold), the synthesized PAA-b-PNIPAAm-b-PCL-SH triblock copolymer may be used for photothermal therapy and theranostic applications.