Triazole-based nano-objects by polymerization induced self-assembly and modification of triazole motifs

Abstract

The rational design of self-assembled architectures with reactive and functional units via polymerization-induced self-assembly (PISA) has attracted growing interest, and is currently the most extensively studied field in nanotechnology, having various potential applications. Herein, we demonstrate the design and synthesis of triazole-based nano-objects from poly(N-vinyl-1,2,4-triazole) (PNVTri) via PISA. Nonionic PNVTri was employed as a hydrophilic macro-chain transfer agent (macro-CTA) for the reversible addition–fragmentation chain-transfer (RAFT) dispersion polymerization of styrene (St). By tuning the solvent polarity using alcohol-based mixed solvents and the polymerization conditions (St/macro-CTA ratio, polymerization time, and temperature), various PNVTri-b-PSt assembled structures (e.g., spheres, worms, vesicles, and nanotubes) were obtained. PISA of St and N-phenylmaleimide (PMI) using the PNVTri macro-CTA enabled more efficient monomer conversion and manipulation of the assemblies to yield structures including nanotubes. PISA of St and divinylbenzene (DVB) afforded stable assemblies that were complexed with zinc(II) trifluoromethanesulfonate. Zinc-complexed nanostructures were also formed by complexation of the PNVTri shell portion of the PNVTri-b-PSt assemblies while maintaining the morphologies formed during PISA. The RAFT dispersion polymerization of St using ionized PNVTri macro-CTA enabled modulation of the surface charge of the cationic assembled structures, which can be regarded as ionic liquid-based polymeric nano-objects. This study is the first example of the successful integration of triazole chemistry and PISA, allowing the expansion of polymeric assembled architectures with unique functionalities and a range of potential applications.