Cationic Bottlebrush Copolymers from Partially Hydrolyzed Poly(oxazoline)s

Cationically charged bottlebrush copolymers were produced by hydrolysis of poly(2-ethyl-2-oxazoline) (PEtOx). The cationic ring-opening polymerization of EtOx was initiated using a styrene derivative to produce PEtOx macromonomers with two different lengths. After detailed characterization, these macromonomers were polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization in a grafting-through process. The length of the bottlebrush backbone was varied, and it was found that a good control over the polymerization could be retained up to backbone DP 50. Hydrolysis of PEtOx repeating units under acidic conditions afforded cationic bottlebrushes, with a defined charge content that could be adjusted by changing the hydrolysis reaction time. Bottlebrush copolymers were analyzed in detail using size-exclusion chromatography, small-angle neutron scattering, and atomic force microscopy indicating a cylindrical topology and an increasing flexibility with increasing chain length.

Automated summary

Cationically charged bottlebrush copolymers were synthesized through hydrolysis of PEtOx, showing control over polymerization up to backbone DP 50. Adjusting charge content was possible by changing hydrolysis reaction time, with structural analysis revealing a cylindrical topology of the copolymers.