CAREER: Placing Single Vinyl Ethers within Synthetic Polymers

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, C. Adrian Figg of Virginia Tech will develop methods to precisely place chemical groups within polymer chains. The importance of polymer sequences on resulting material properties is largely unknown due to the limited number of ways to precisely place functional groups within polymers. However, learning the structure–function relationships of polymers is critical to designing better materials and integrating polymers into underexplored research areas (for example, biomedical science, drug delivery, responsive materials). This research will use light activated catalysts to control the exact number of chemical groups at multiple sites within polymers. To achieve this goal, the polymer composition and reaction rates will be measured to identify how to incorporate single sites of functionality within polymers. An educational component will develop a mail-order science kit for high schoolers to learn photochemistry and discover polymer antimicrobials. The broader impacts of this work include developing the next generation of STEM professionals by training students to use precision polymer chemistry to tackle global issues such as developing compatibilizers for recycling, high-performance plastics, and materials for biomedical science, antimicrobials, and therapeutics. The Figg lab aims to use photocatalysts to controllably place single vinyl ether units within vinyl polymers to achieve multisite-defined copolymers. Photoinduced electron/energy transfer chemistry will be used in combination with reversible addition-fragmentation chain-transfer (RAFT) polymerization to controllably synthesize polymers. The slow polymerization kinetics of vinyl ethers will be used to place exactly one monomer at defined positions via a single unit monomer insertion reaction. The effect of polymer identity (for example, polyacrylate vs. polymethacrylate vs. polystyrenic) on vinyl ether addition will be studied through kinetic measurements. Multiple sites of insertion will be developed where the maximum number of sites will be determined according to reaction conversions. This research will enhance our fundamental understanding of the kinetics of RAFT polymerization and the influence this has on controlling sequence in multisite-defined RAFT copolymers. These advances will enable the synthesis of multisite-defined vinyl copolymers, where the identity, number, sequence, and relative of position of single vinyl ethers are all controllable, approaching the complexity of the sequence-defined nature of biological polymers, such as proteins and oligonucleotides. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.