Temperature and pH responsive raspberry-like hollow nanoparticles prepared by seed photopolymerization under green LED irradiation

Abstract

Hollow polymer nanoparticles have garnered significant attention in sensing, catalysis, and biomedical applications due to their unique structural properties. To develop a novel synthetic approach of dual-responsive hollow nanoparticles, a visible-light-initiated photopolymerization strategy under green LED irradiation was established. First, monodisperse poly(methyl methacrylate) (PMMA) nanoparticles were synthesized via dispersion photopolymerization. These nanoparticles served as seeds for subsequent seed photopolymerization, enabling the formation of raspberry-like core-shell structures with different sizes and surface morphologies by adding different dosages of secondary stimuli-responsive monomers N-isopropylacrylamide (NIPAM) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). Finally, solvent etching was employed to remove the PMMA seeds, producing hollow polymer nanoparticles with controllable temperature and pH responsiveness.