Quantifying and Leveraging Interfacial Amine Reactivity in Block Copolymer Nanoparticles for Advanced Material Design

The rational design of functional nanomaterials requires precise control over molecular architecture and interfacial reactivity. Here, we report the synthesis of amine-functionalized block copolymer nanoparticles via aqueous polymerization-induced self-assembly, combining synthetic efficiency with rigorous characterization to bridge molecular design and macroscopic functionality. The incorporation of 2-aminoethyl methacrylate into a macrochain transfer agent enabled the formation of stable, monodisperse nanoparticles while providing quantifiable interfacial amines for postassembly modification. Near-quantitative conjugation with fluorescein isothiocyanate (86% yield) or thermoresponsive poly(N-isopropylacrylamide) (91% efficiency) demonstrated the platform versatility, with the latter exhibiting a tunable lower critical solution temperature transition at 41°C. Furthermore, the nanoparticles could be self-assembled into crosslinked colloidosomes, highlighting their potential as modular building blocks for the fabrication of hierarchical architectures. This work establishes a paradigm for engineering functional polymeric nanomaterials with tailored properties, offering transformative opportunities in drug delivery, diagnostics, and nanoreactor design. By linking molecular-scale precision to predictable performance, our approach advances the field from empirical optimization to true molecular engineering of polymeric nanoparticles.