Abstract
A novel monomer, 4-azido-2,3,5,6-tetrafluorobenzyl methacrylate (ABMA), enabled the selective and efficient postpolymerization modification of RAFT-made homopolymers and diblock copolymer nanoparticles prepared through polymerization-induced self-assembly (PISA). Poly(ABMA) homopolymers were modified postpolymerization in (near-)quantitative conversions with phosphines to give stable iminophosphoranes and in a multicomponent reaction with phenylacetaldehyde and morpholine, piperidine, or the crosslinker N,N’-dimethylethylene diamine to give the corresponding amidine derivatives in one step. Product polymers were characterized by NMR and FT-IR spectroscopy, size-exclusion chromatography, and differential scanning calorimetry. Unlike its monomer, poly(ABMA) was insoluble in ethanol and enabled the preparation of well-defined spherical, worm-shaped, and vesicular nanoparticles with azide-functional cores through RAFT dispersion polymerization with concurrent PISA. Worm-shaped particles formed physical gels that underwent thermally reversible degelation. Multicomponent modification of spherical nanoparticles with phenyl acetaldehyde and morpholine or piperidine led to (near-)quantitative core modification and, for morpholine, a significant increase in sphere diameter. UV-irradiation of nanoparticles led to crosslinking through the formation of reactive nitrene intermediates which prevented the disassembly of nanoparticles in non-selective solvents, representing a simple and reagent-free crosslinking strategy, and expanding the scope of azide-based polymer chemistry.