Synthesis of Poly(vinyl acetate) Molecular Brushes by a Combination of Atom Transfer Radical Polymerization (ATRP) and Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization

Well-defined PVOA (poly-(vinyl alcohol) molecular brushes were prepared using a combination of ATRP (atom transfer radical polymerization) and RAFT (reversible addition-fragmentation chain transfer) polymerization techniques. Ethyl xanthate was selected as CTA, since it is an efficient chain transfer agent for VOAc polymerization. 2-Bromopropionic acid was reacted with potassium xanthate to form a secondary xanthate species with acid functionality (XA) as a yellow liquid. To obtain PPXEM-g-PVOAc brush copolymers, PVOAc side chains were grown from PPXEM multifunctional macro-CTA by RAFT in the presence of AIBN. Molecular imaging of Langmuir-Blodgett films was used to measure the number-average was used to measure the number-average molecular weights of the brushes. Imaging of individual brush macromolecules by AFM confirmed the well defined architecture of the molecular brushes, with a characteristic chain extended conformation.