Mechanochemical\nSynthesis of Ionic Polymers: Solid-State\nBall-Milling Polymerization for Unrestricted\nSolubility Enabling Copolymerization of Immiscible Monomers

This study demonstrates the facile synthesis of ionic\npolymers\nusing a solid-state mechanochemical ball milling method, which offers\na straightforward, ecofriendly, and broad scope compared to conventional\nsolution polymerization techniques. Unlike solution polymerization,\nwhich is limited by solvent selection and often results in poor efficiency,\ndirect ball-milling polymerization enables the production of the desired\nproduct polymers from a broader range of ionic monomers without solubility\nand miscibility constraints. We employed free-radical polymerization\nof styrene and (meth)acrylic ionic monomers, as well as Ru-initiated\nring-opening metathesis polymerization of norbornenyl ionic monomers,\nto demonstrate the effectiveness of the mechanochemical approach.\nAdditionally, the study explored the mechanochemical copolymerization\nof immiscible monomer pairs such as sodium carboxylate/pyrene and\nammonium sulfone betaine/porphyrin moieties, producing water-soluble\nporphyrin and pyrene polymers. Overall, this research showcases mechanochemistry’s\nversatility and efficiency in synthesizing ionic polymers, anticipating\nits use in various applications.