Synthesis by RAFT polymerization and properties of anionic cylindrical molecular brushes bearing poly(acrylic acid) side chains

RAFT polymerization of acrylic acid (AA) in the presence of low-molecular chain transfer agent (2-(butylthiocarbonothioylthio) propanoic acid and polyacrylate-based backbone bearing multiple butylthiocarbonothioylthio moieties is reported demonstrating successful synthesis of linear pAA with low polydispersity and anionic cylindrical molecular brushes, respectively. Twofold excess of butylthiocarbonothioylthio moieties attached to polyacrylate-based backbone over the initiator was optimal enabling to synthesize graft copolymers with rather low polydispersity (PDI 1.23-1.36) and reasonably high DP of pAA side chains (up to 25). Anionic cylindrical molecular brushes were characterized by SEC with triple detection, DLS, 1H NMR spectroscopy, and potentiometric titration. Thermal transitions and thermal stability of the brush polymers bearing pAA side chains were determined by DSC and TGA.