Synthesis of Hydrophobic Block Copolymer Nanoparticles in Alcohol/Water Stabilized by Poly(methyl methacrylate) via RAFT Dispersion Polymerization-Induced Self-Assembly

Abstract

Poly(methyl methacrylate) (PMMA) is an important common polymer widely used in industry. While PMMA has been used as a core-forming block for polymerization-induced self-assembly (PISA), a powerful approach for the synthesis of block copolymer nanoparticles, it has not been utilized as a corona block due to PMMA being insoluble in common solvents for PISA formulations (e.g., water and alcohols). Exploiting the solubility of PMMA-dithiobenzoate (DTB) in ethanol/water mixtures, such macroRAFT agents have in the present work been successfully employed for reversible addition–fragmentation chain transfer (RAFT) PISA in ethanol/water (80/20 by volume). RAFT dispersion polymerization of benzyl methacrylate mediated by PMMA-DTB macroRAFT agents with various degrees of polymerization has been investigated. Transmission electron microscopy analyses revealed well-defined block copolymer nano-objects, including spheres, worms, as well as vesicles. Nanoparticles comprising a PMMA outer layer would have superior compatibility with various hydrophobic polymer matrices, thereby enabling various new applications such as, e.g., use as nanofillers.