Free radical polymerization of methacrylates in ionic liquids

Imidazolium salts with a modified structure of both, the cation and the anion have been investigated as solvents for polymerization of hydrophobic and hydrophilic monomers. Thermal properties and viscosity of the imidazolium salts are important for their selection as reaction media in polymerization processes. The molecular weight of poly(n-butylmethacrylate) is higher if ionic liquids were used for synthesis in comparison with a conventional solvent. Furthermore, copolymers based on hydrophobic and hydrophilic monomers were successfully synthesized using imidazolium salt as solvent. The amount of the ionic liquid recycled after polymerization without any solvent or by using a traditional solvent depends on both the structure of the polymer and the properties of the imidazolium salt. In case of polymeric sulfobetaines, approximately equimolar amounts of imidazolium salt are bound ionically by the sulfobetaine moiety incorporated in the polyzwitterion.