Synthesis, characterization, and bulk crosslinking of polybutadiene-block-poly(2-vinyl pyridine)-block-poly(tert-butyl methacrylate) block terpolymers

We report on the synthesis and characterization of triblock terpolymers, polybutadiene-block-poly(2-vinyl pyridine)-block-poly(tert-butyl methacrylate) (PB-b-P2VP-b-PtBMA; BVT), via sequential living anionic polymerization in THF at low temperatures using sec-butyl lithium as initiator. In this work, 18 different BVT terpolymers were produced with volume fractions ΦB : ΦV : ΦT in the range of 1 : 0.4…1.2 : 0.2…4.6. All polymers exhibit a very narrow molecular weight distribution (PDI < 1.1). They were characterized in terms of bulk morphology using small-angle X-ray scattering and transmission electron microscopy, unveiling mostly lamellar patterns or hexagonally arranged cylindrical structures. Some polymers displayed a partial gyroid structure coexisting with lamellar parts or cylinders with a non-continuous shell around the PB core and could serve as an interesting template for the facile generation of multi-compartmental self-assembled structures. In one case the middle block, P2VP, is forming a helix around the PB core. Crosslinking of the polybutadiene compartment of the bulk morphologies with an UV-photoinitiator was performed, followed by sonication-assisted dissolution of the aggregates to elucidate further use of the terpolymers for the generation of soft polymeric nanoparticles with controlled functionality. In that way, core-crosslinked cylindrical micelles could be generated and characterized.