NSF-ANR CHE: Stereocontrolled Radical Polymerization of Linear and Cyclic Vinyl Monomers Through Cobalt-Based Metalloradical Catalysis

About This Grant

In this project funded by the Chemistry Division, Professors Jia Niu and X. Peter Zhang of the Department of Chemistry at Boston College in the United States is collaborating with Professor Julien Nicolas at University Paris-Saclay/CNRS in France, funded by the French National Research Agency (ANR), to develop a sustainable method to make biodegradable plastics. A key focus of this research is controlling the three-dimensional orientation of the building blocks, also known as the stereochemistry, of the plastic molecules. Each of these building blocks can have two mirror-image stereochemistries that are not interchangeable, and collectively the stereochemistry of all building blocks in these plastics can dramatically affect how they behave as materials, such as their strength, at what temperature they melt, or how easily they break down. Traditional methods for controlling the building block stereochemistries in plastics often require harsh conditions and/or rare metal elements. This project develops a new strategy that employs earth-abundant cobalt element to guide how building blocks of a plastic molecule are arranged during the reaction in which it forms. If successful, the technology developed in this project could be used to produce functional plastics with stereochemistry-determined properties for delivering drug molecules to the targeted sites or packaging materials that can be broken down in the natural environment. The project also includes U.S. and France student exchanges and bilingual science education programs that give students hands-on trainings in sustainable chemistry, helping to train a globally minded scientific workforce. This project aims to develop cobalt-based metalloradical catalysis (MRC) that leverages cobalt-bound organic radicals to control both the activity and stereochemistry of radical polymerization across a broad range of monomers, a long-standing challenge in polymer chemistry. Specifically, the research will answer the following fundamental questions: (1) Can metalloradical catalysis be used to achieve stereocontrolled radical polymerization of acyclic vinyl monomers, and how do different cobalt catalyst designs influence the resulting polymer tacticity? (2) Is it possible to extend this stereocontrol to radical ring-opening polymerization and copolymerization of cyclic vinyl monomers, enabling the synthesis of degradable polymers with tailored properties? (3) Can the inherent chirality of stereoregular polymers be harnessed to drive tacticity-induced self-assembly (TISA), and how does it influence the morphology and function of polymer-based drug delivery systems? By integrating experimental and computational approaches, this work will deepen mechanistic understanding of stereocontrol in radical polymerization and establish a broadly applicable, catalyst-controlled platform for producing tacticity-controlled degradable vinyl polymers. The use of earth-abundant cobalt not only advances sustainable catalysis in polymer synthesis but also opens new pathways for reducing plastic waste. 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.