Hybrid Bonding Polymers

Northwestern University, Evanston IL

Investigators

Abstract

Part 1: NON-TECHNICAL SUMMARY The development of new technologies relies on the discovery and design of new materials. Polymers have been of critical importance over the past century for the production of consumer goods, manufacturing systems, transportation, construction, and medical products, among others. These lightweight soft materials are produced with chemicals known as monomers that react to form extremely large molecules (macromolecules) that have posed challenges in sustainability such as the widely known problem of plastic pollution. Over the past few decades, the opportunity has emerged to create new materials known as “supramolecular polymers” in which monomers do not react to form macromolecules but instead are designed to strongly interact and emulate properties of traditional polymers. These structures tend not to be as mechanically robust as traditional polymers but could facilitate recycling and biodegradation, and also generate materials for advanced applications in energy, electronics, and medicine. This project investigates strategies to develop new materials termed “hybrid bonding polymers” which integrate traditional and supramolecular polymers to create sustainable systems that have suitable mechanical properties and potential for new technologies. The project will train undergraduate, graduate, and postdoctoral students--including those from underrepresented groups--in highly interdisciplinary research needed for future technical challenges at the interface of synthetic organic chemistry, polymer chemistry, and materials science. Researchers supported by the grant will be encouraged to participate in science outreach programs for K-12 students in the Chicago area. PART 2: TECHNICAL SUMMARY The integration of macromolecules and supramolecular polymers in which covalent and noncovalent bonds are rationally integrated has great potential as a key innovation in soft materials. In these “hybrid bonding polymers”, small molecules forming supramolecular domains could be co-crystallized with covalent polymers functionalized with the same molecules. This can generate functional structures in which polymer backbones with mechanical benefits are covalently connected to sites of crystalline lattices. Hybrid bonding could also generate more sustainable structures than fully covalent polymers in which high value-added small molecules can be easily recycled. The proposed work will develop and investigate these unique structures, their self-assembly mechanisms, and also the properties of experimental materials. Specifically, systems to be investigated will include crystallizable chromophores such as electron donors and acceptors as well as photosensitizers targeting properties such as photocatalysis, ferroelectricity, and supramolecular chirality. It is envisioned that potential applications could include light harvesting materials for photocatalytic solar fuel production, energy-efficient data storage, and sensing, among others. Beyond the potential technological impact, the studies proposed here will provide valuable cross disciplinary training to undergraduate, graduate, and postdoctoral students from both chemistry and materials science and engineering programs. The cohort of students will include members of underrepresented groups who will receive ample support from the PI and other members of the laboratory. Additionally, students and postdoctoral fellows working on this project will be encouraged to participate in K-12 science outreach programs that are available through the University. . 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.