Solvent Effects on ATRP of Oligo(ethylene glycol) Methacrylate. Exploring the Limits of Control

Abstract

Five copper complexes in combination with six monomer−solvent mixtures have been used to investigate the solvent effects on ATRP of oligo(ethylene glycol) methacrylate (OEGMA). The redox properties of the copper complexes in OEGMA−solvent mixtures and the apparent rate constants (kpapp) for ATRP of OEGMA were correlated to the degree of control over the polymerizations. Based on this correlation, a general discussion of the limits of control in ATRP is carried out. One of the key parameters for control in ATRP is the propagation rate constant, making the choice of monomer essential for the design of an ATRP system. Also, the solvent effects on the ATRP equilibrium constant (KATRP) affect the limit of control (i.e., the apparent rate constant above which control is lost). The choice of copper complex is also more important than the choice of solvent for the design of a well-controlled ATRP system.