Diblock Copolymer Nanoparticles Bearing Phenols: Potential Stimuli-Responsive Pickering Emulsifiers with Antioxidant and Antibacterial Activities

Core–shell structure diblock copolymer nanoparticles carrying phenolic groups in the core domain were prepared through the combination of RAFT-mediated dispersion polymerization and the hydrolysis of postpolymerization in this study. Poly(2-(dimethylamino)ethyl methacrylate)23 (PDMAEMA23) was first synthesized through RAFT-mediated solution polymerization, which was then utilized as macro-CTA to mediate the dispersion polymerization of 4-tert-butoxystyrene (tBOS) in isopropanol/water (8:2, v/v) mixtures. PDMAEMA23-PtBOSx diblock copolymer nanoparticles with different morphologies, including spheres, worms, and vesicles, were produced. Subsequently, the selected PDMAEMA23-PtBOS490 vesicles underwent hydrolysis in an acidic environment. During the hydrolysis, tBOS repeat units were partially converted into 4-vinylphenols (VPl), affording polymer nanoparticles bearing phenolic groups in the core domain, accompanied with a gradual morphological transition from vesicles to spheres. The content of VPl units in the core domain could be flexibly adjusted by varying the hydrolysis time. The as-prepared diblock copolymer spheres demonstrated a unique combination of stimuli-responsive emulsifying performances and intrinsic antioxidant activity, as well as antibacterial effectiveness.