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 <i>a</i>-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 the first catalyst-controlled stereoselective polymerization of vinyl ether monomers. We demonstrate that this method is general to vinyl ether substrate, providing access to a range of isotactic poly(vinyl ether)s with previously unprecedented degrees of isotacticity. The obtained materials represent a new class of thermoplastics with a unique combination of mechanical and surface properties. Isotactic poly(vinyl ether)s display the tensile properties of commercial polyolefins but have an order of magnitude stronger adhesion to polar substrates, indicating their promise for next generation engineering applications.

Stereoselective cationic polymerization of vinyl ethers

ACS Fall 2020 Virtual Meeting

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