Synthesis of Amphiphilic\nPoly(<i>N</i>-vinylpyrrolidone)-<i>b</i>-poly(vinyl\nacetate) Molecular Bottlebrushes

Abstract

Well-defined molecular bottlebrushes with poly­(<i>N</i>-vinylpyrrolidone) and poly­(<i>N</i>-vinylpyrrolidone)-<i>b</i>-poly­(vinyl acetate) (PNVP-<i>b</i>-PVOAc) side\nchains were prepared via a combination of atom transfer radical polymerization\n(ATRP) and reversible addition–fragmentation chain transfer\n(RAFT). A macro chain transfer agent poly­(2-((2-ethylxanthatepropanoyl)­oxy)­ethyl\nmethacrylate) (PXPEM) was prepared by attaching xanthate chain transfer\nagents onto each monomeric unit of poly­(2-hydroxyethyl methacrylate).\nSubsequently, a RAFT polymerization procedure was used to synthesize\nmolecular bottlebrushes with PNVP side chains with controlled molecular\nweight and low polydispersity by grafting from the PXPEM backbone.\nThe side chains were then chain extended with PVOAc, yielding a bottlebrush\nmacromolecule with PNVP-<i>b</i>-PVOAc side chains. The\ncomb-like shape of the chain extended bottlebrushes was confirmed\nby atomic force microscopy (AFM).