Direct Sequential Block Copolymerization of a Highly Polarity-Mismatched Monomer Pair

Abstract

Access to smaller phase domain dimensions requires reducing the degree of polymerization, which weakens segregation and increases the importance of strong segmental incompatibility; however, the same chemical contrast can impede direct sequential block copolymerization through differences in solvent affinity. Here, we synthesized poly(hexafluorobutyl acrylate)-block-poly(acrylamide) (PHFBA-b-PAAm) in one pot from 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) and acrylamide (AAm) using organotellurium-mediated radical polymerization (TERP), without intermediate purification or solvent exchange. Although AAm addition induced micron-scale aggregation at room temperature, the system reorganized into a nanoscale dispersion under polymerization conditions, supporting high-conversion chain extension with low dispersity. Well-defined block copolymers with molecular weights of 15–100 kDa and varied compositions were obtained at high monomer conversions. Small-angle X-ray scattering and atomic force microscopy revealed microphase separation throughout the series, including the 15 kDa sample. Overall, direct synthetic access and low-molecular-weight phase separation can be reconciled in block copolymers with strongly incompatible segments.