Tadpole-shaped amphiphilic block-graft copolymers prepared via consecutive atom transfer radical polymerizations

Tadpole-shaped (or rod-coil) block-graft copolymers, consisting of a pentafluorostyrene polymer (PFS) block and a glycidyl methyacrylate polymer (PGMA) block with grafted poly(tert-butyl acrylate) (PtBA) side chains, or PFS-b-(PGMA-g-PtBA) copolymers, were synthesized by consecutive atom transfer radical polymerizations (ATRP's). The process involved W synthesis of PFS via ATRP, (ii) synthesis of well-defined PFS-b-PGMA via ATRP, (iii) coupling of the bromoacid initiators with the glycidyl methacrylate units in the PGMA block to generate the PFS-b-PGMA macroinitiators, and (iv) ATRP-mediated graft copolymerization with tert-butyl acrylate to generate the PFS-b-(PGMA-g-PtBA) copolymer. Hydrolysis of the PtBA side chains in the block-graft copolymer into the acrylic acid polymer (PAAC) side chains gave rise to an amphiphilic PFS-b-(PGMA-g-PAAC) macromolecule with a brush-shaped hydrophilic head (rod) and a hydrophobic tail (coil). The copolymers were characterized by composition analysis, gel permeation chromatography (GPC), thermogravimetric analyses (TGA), nuclear magnetic resonance (NMR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The macromolecular architecture of the copolymer was suggested by atomic force microscopy (AFM) images and micelle formation.