Responsive single-chain polymer nanoparticles with host–guest features

We report a facile approach to form ultra-fine single-chain polymer nanoparticles (SCPNs) via disulfide-based intrachain crosslinking of single polymer chains of a random copolymer poly(HEMA-co-PDSEMA). The SCPNs, which were prepared under mild reaction conditions and at normal reaction concentrations (up to 10 mg mL−1), have been characterized by 1H nuclear magnetic resonance (1H NMR) spectroscopy, atomic force microscopy (AFM), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and dynamic light scattering (DLS). The influences of the crosslinking density, the molecular weight and the initial concentration of the polymer upon the formation of SCPNs are also reported. In order to investigate the hydrophobic interior of SCPNs, we trace the emission spectrum of a pyrene probe. We highlight that these SCPNs exhibit host–guest properties to stably encapsulate hydrophobic guest molecules and release them in response to a redox stimulus.