Synthesis of morphologically diverse dual thermo- and pH-responsive nano-objects via RAFT-mediated emulsion PISA

Abstract

We report a versatile and efficient strategy for the synthesis of dual thermo- and pH-responsive polymeric nano-objects with rich morphological diversity, achieved via RAFT-mediated aqueous emulsion polymerization-induced self-assembly (PISA). Using a thermoresponsive poly(triethylene glycol methyl ether methacrylate) (PTEGMA) macro-chain transfer agent and a pH-sensitive diisopropylaminoethyl methacrylate (DPA) monomer, we generated PTEGMA-b-PDPA diblock copolymer nano-objects under conditions both below and above the LCST of PTEGMA. By systematically varying the length of the PDPA block, we accessed a wide array of morphologies—including micelles, worms, vesicles, and intricate “octopus”-like structures—simply by adjusting the polymerization temperature and hydrophobic block length. These nanostructures displayed clear dual responsiveness: thermally triggered aggregation around ∼40 °C and reversible disassembly in acidic environments. Our findings highlight the precise morphological control achievable through aqueous RAFT-PISA and underscore its potential for designing smart nanomaterials tailored for biomedical and stimuli-responsive applications.