RT-Controlled Radical Polymerization

Significance

Controlled free radical polymerizations allow for the formation of polymers with controlled molecular weight. A major advantage of atom transfer radical polymerization (ATRP) is that the initiators are readily attached to a variety of substrates and the radical concentrations are maintained at a sufficiently low concentration to prevent chain termination reactions even when the growing chains are propagating from a surface. This method involves the use of a bimetallic catalyst that is modified to create greater solubility and has a high activity at ambient or slightly elevated temperature. It is proposed that the active species is a mixed valence Ru(II)-Ru(III) complex. Polymerizations displayed a linear relationship between Mn and conversion, indicative of a living polymerization.