CAREER: Development and Applications of Photocontrolled Cationic Polymerizations

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Professor Brett P. Fors of Cornell University is supported by the Macromolecular, Supramolecular, and Nanochemistry (MSN) program of the Division of Chemistry to develop new synthetic methods for the preparation of polymers with control over chemical structures and properties. This approach takes advantage of interesting characteristics of visible light to enable the synthesis of previously inaccessible polymer architectures. The properties of polymeric materials are directly controlled by chemical structure and the methods developed in this project enable the synthesis and utilization of improved polymeric materials for applications in adhesives, elastomers, and electronics. Educational activities are integrated into this project. The focus of these activities is on the development of a polymer science summer camp that exposes Native American students to Science, Technology, Engineering and Mathematics (STEM) education and research at an early age. The objective is to stimulate the interest of Native American students in STEM related fields.The project develops a cationic polymerization process for vinyl ethers that is regulated by visible light through the reversible oxidation of a polymer chain end with a photocatalyst. Precise spatial and temporal control over polymer chain growth is achieved by the photoinitiated reversible formation of a propagating cation. This cationic polymerization process is being used in combination with other photocontrolled radical polymerization processes to enable switching between different polymerization mechanisms. Monomer selectivity in situ is achieved by modulating the wavelength of irradiation. This protocol provides control over polymer sequence with an external stimulus and allows the synthesis of previously inaccessible polymer structures. Additionally, similar strategies are being developed for photocontrolled polymerization of epoxides, thus extending the scope and expanding the practicality of this approach. Synthetic polymers are of importance in all aspects of modern life and have facilitated major societal advances. Innovative synthetic methods are required to enable the synthesis of complex materials with unknown function. Photocontrolled cationic processes allow for the development of new polymeric structures with previously inaccessible architectures. Importantly, high levels of spatial and temporal control gained in photocontrolled polymerizations facilitate the application of these new methods in fields such as lithography, coatings, and biology. This award enables the establishment of a polymer science camp on the Flathead Indian Reservation in collaboration with the Salish and Kootenai College. This summer camp introduces Native American students to research activities at an early age in order to increase their interest and participation in STEM fields. Additionally, through workshops for teachers on the Flathead Indian Reservation the quality of STEM related education increases for elementary and middle school Native American students. These efforts contribute to creating a diverse STEM workforce in the United States.