Exploring RAFT polymerization for the synthesis of bipolar diblock copolymers and their supramolecular self-assembly

Abstract

Until recently, the primary controlled radical polymerization (CRP) technique used to synthesize side chain semi-conducting block copolymers from vinyl monomer species has been nitroxide-mediated polymerization (NMP). The potential exploitation of reversible addition fragmentation chain transfer (RAFT) polymerization for the preparation of semi-conducting diblocks has not yet been fully realized. In this work a trithiocarbonate chain transfer agent (CTA) has been shown to polymerize both hole transporting (HT) monomers m-vinyltriphenyl amine and p-vinyltriphenyl amine and also a new fluorinated triphenylamine monomer for the first time, affording both homopolymers and diblock copolymers with good control over molecular weight (M_n) and narrow polydispersities (M_w/M_n). The electronic properties of these blocks and diblocks were explored using UV-vis and cyclic voltammetry analysis. The selective self-assembly of these diblocks into solution nanostructures has been explored and characterized by DLS and TEM analysis.