One-pot direct synthesis of novel antibacterial diblock copolymers-based-vinyl acetate via RAFT polymerization

The one-pot route has been adopted for direct synthesis of novel Poly(vinyl acetate-co-1,3-divinyltetramethyldisiloxane), Poly(vinyl acetate-co-4-vinylbenzyl chloride) and Poly(vinyl acetate-co-vinyltriphenylphosphonium bromide) diblock copolymers via reversible addition-fragmentation chain transfer (RAFT) polymerization of vinyl acetate with a variety of comonomers such as 1,3-divinyltetramethyldisiloxane, 4-vinylbenzyl chloride and vinyltriphenyl phosphonium bromide using cyanomethylmethyl(phenyl) carbamodithioate as RAFT agent. These RAFT copolymers have been characterized by standard spectroscopic methods viz. FTIR, C-13-NMR, UV-visible absorption spectroscopy and gel permeation chromatography. The multi instruments studies of obtained diblock copolymers show that these are successfully formed as a result of RAFT. Their thermal stabilities have been investigated by thermogravimetric analyses and differential scanning calorimetry. The physio-chemical properties of each copolymer such as ionic conductivity, density, and intrinsic viscosity have also been evaluated. Further, they are tested in vitro, using disc diffusion and broth dilution methods against two Gram positive (S. aureus and B. subtilus) bacteria and three Gram negative bacteria (S. typhi, E. coli and P. aeruginosa). A broad spectrum and strongest antibacterial activity suggested that these RAFT copolymers have potential as antibacterial agents.