Title: Stereoselective Cationic Polymerization of Prochiral Monomers
Abstract: The stereochemistry of vinyl polymers, known as polymer tacticity, is intimately linked to their resultant material properties. Despite the well-developed stereoselective methods for the polymerization of propylene and other nonpolar -olefins, general approaches to the stereoselective polymerization of polar vinyl monomers are not well developed. In this lecture, we will discuss the design of chiral counterions that systematically tune the reactivity and chain-end stereochemical environment during cationic polymerization. This approach overrides conventional chain-end stereochemical bias to achieve catalyst-controlled stereoselective polymerization of prochiral vinyl monomers through a cationic mechanism. We demonstrate that chiral counterion catalysis is a general conceptual approach that can be leveraged for the stereoselective polymerization of both vinyl ethers and N-vinyl carbazoles. The properties of the isotactic polymers will also be described, with a focus on how unique function can be derived from stereocontrol.