CAREER: Mechanical Properties of Ultrathin Polymer Films

PART 1: NON-TECHNICAL SUMMARY Many industrial applications rely upon strong and stable polymer thin films. Examples of applications include flexible (bendable) electronic devices, very thin plastic membranes for separation, or multilayer plastic films for protection. Such related technologies are critical for diverse uses in improving health monitoring and diagnosis, cleaning air and water, and increasing food shelf life and solar cell stability through barrier protection. Designing mechanically stable and thinner polymer films for these applications will lower the cost of materials, reduce the energy requirements for filtration, and decrease the amount of plastic ending up in landfills. However, when polymer materials are processed into thinner films, mechanical strength is known to change, but how those changes depend on temperature and how they attach to different substrates remains unclear. Using recently developed techniques, the PI will directly study the mechanical properties of ultrathin polymer films and provide new fundamental data and knowledge to guide the production of polymer materials for better adhesives, membranes, coatings, and many other technologies. The proposed research will provide a strong foundation for the education and training of graduate and undergraduate researchers. In addition to research efforts, new curriculum will be designed to inspire high school students across Colorado and Hawaiʻi to explore and pursue advanced degrees and careers in STEM disciplines. These curriculum materials for high school classrooms and summer programs will be developed to align materials science and engineering lessons with traditional Indigenous knowledge. PART 2: TECHNICAL SUMMARY The objective of this CAREER project is to develop an inclusive research and educational program dedicated to understanding the mechanics of polymers, with a special emphasis on systems that are traditionally difficult to characterize, such as ultrathin films (< 100 nm). The primary research goal is to elucidate how structure and dynamics at the surface of the film affect the mechanical properties of ultrathin polymer films. The PI’s research group will systematically evaluate thickness-induced changes in the tensile and fracture properties in ultrathin polymer films as a function of (1) surface mobility, (2) crosslinking, and (3) surface interactions. This work will advance the development of nanotechnologies with long-term thermomechanical stability. The research goal will be integrated with an educational outreach program focusing on connecting Western materials science knowledge to Indigenous knowledge to increase recruitment and retention of students in STEM, with a focus on broadening participation, including Native Hawaiians. This will be achieved in three stages: 1) curriculum development through a pilot program at a local Colorado high school, 2) development and implementation of short-form curriculum materials for broader dissemination in Colorado and Hawaii, and 3) undergraduate exposure to materials research. 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.