Controlled radical polymerization of 2-hydroxyethyl methacrylate with a hydrophilic ruthenium complex and the synthesis of amphiphilic random and block copolymers with methyl methacrylate

A hydrophilic ruthenium complex with ionic phosphine ligands [1: RuCl2[P(3-C6H4SO3Na)(C6H5)(2)](2)} induced controlled radical polymerization of 2-hydroxyethyl methacrylate (HEMA) in methanol under homogeneous conditions; the initiator was a chloride (R-Cl) such as CHCl2COPh. The number-average molecular weights of poly(HEMA) increased in direct proportion to monomer conversion, and the molecular weight distributions were relatively narrow (M-w/M-n = 1.4-1.7). A similar living radical polymerization was possible with (MMA)(2)-Cl [(CH3)(2)C(CO2CH3)CH2C(CH3)(CO2CH3)Cl] as an initiator coupled with amine additives such as n-Bu3N. In a similar homogeneous system in methanol, methyl methacrylate (MMA) could also be polymerized in living fashion with the R-Cl/1 initiating system. Especially for such hydrophobic polymers, the water-soluble ruthenium catalyst was readily removed from the polymers by simple washing with an aqueous dilute acid. This system can be applied to the direct synthesis of amphiphilic random and block copolymers of HEMA and MMA. (C) 2002 Wiley Periodicals, Inc.