Post-Polymerization Editing of Polymer Tacticity

The tacticity of polymers impacts their macroscopic properties. Methods to precisely 10 control polymer tacticity prior to or during polymerization are well known; however, postpolymerization editing of tacticity remains underexplored. Here, we report a strategy for visible light-driven polymer tacticity editing through continuous C–H exchange at stereogenic sites along the polymer backbone. This approach can transform isotactic polymers into a library of products with varying tacticities and can provide access to stereoenriched polymers from atactic starting 15 materials. Spatiotemporal control over tacticity editing enabled the patterning of heterogeneous mechanical responses within a compositionally uniform material. This platform establishes postpolymerization tacticity editing as a complementary paradigm to stereocontrolled polymerization that provides access to stereoenriched and stereopatterned materials that are challenging to access through conventional synthetic routes.