Compartmentalization of an ABC triblock copolymer single-chain nanoparticle via coordination-driven orthogonal self-assembly

Abstract

Herein, we present supramolecular compartmentalization of an ABC triblock copolymer single-chain nanoparticle (SCNP) using coordination-driven orthogonal intramolecular self-assembly in aqueous solution. A well-defined ABC-type triblock copolymer was synthesized via visible-light-mediated RAFT aqueous sequential block copolymerization. It possesses protonated imidazolium-motifs in the A-, NH₃⁺-motifs in C-, and hydroxyl-motifs in B-block. Coordination-driven orthogonal self-assembly locally occurring upon deprotonation (A-block within pH 3.3–4.4 and C-block within pH 5.3–6.4) has been evidenced by UV-vis spectroscopy, ¹H NMR, dynamic light scattering (DLS), NMR diffusion-ordered spectroscopy (DOSY), and atomic force microscopy (AFM). A blank regime of pH 4.4–5.3 guarantees locally orthogonal intramolecular self-assembly without mutual interference. Dialysis and pH-cycling results illustrate that the inherent different subdomains are discrete and can individually respond to an external stimulus, with potential biomimetic functions in terms of sub-10 nm ultrafine internal heterogeneity.