CAREER: Development of Force-Activated Materials for the Release of Small Organic Molecules

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

NON-TECHNICAL SUMMARY: Large, observable changes in a material environment can be translated into molecular-scale events, giving rise to chemical reactions at the smallest length scales. A particularly powerful method for communicating between macroscopic and molecular-level events is the development of chemical reactions that can be driven by mechanical force. Toward this end, the PI seeks to develop materials capable of converting mechanical stress, such as compression and elongation, into chemical outputs including the release of small molecule agents. The small molecules that are released may be applicable to therapeutics, catalysts, or reagents, providing advancements in diverse areas such as drug delivery, self-reinforcing materials, and sensors. Undergraduates and graduate students in the Department of Chemistry will be mentored in this program, and will have opportunities to collaborate with experts from chemistry, engineering, and physics disciplines. The PI will also integrate an education plan that incorporates the discoveries and challenges from the research component of the program. This will be achieved through partnership with a local area high school to develop a model for collaboration between university researchers and high school students. The process will include redesigning high school science curricula to include problem-based learning activities that mimic the experiences of undergraduate and graduate researchers at the university level. Anticipated outcomes include increased recruitment and retention of students from underrepresented minority groups in Science, Technology, Engineering, and Mathematics majors. TECHNICAL SUMMARY: This program aims to develop materials capable of releasing small organic molecules via mechanochemical transduction. In this way, macroscopic forces will be translated into molecular-level chemical reactions resulting in triggered covalent bond scission. Toward this end, the PI will investigate and compare complementary isomeric designs for mechanoresponsive functional groups (i.e., mechanophores) that are activated by either bond bending or stretching distortions. A central hypothesis is that these two modes of activation will manifest different efficiencies of energy transduction. Additionally, the solid-state mechanical properties best suited for activation of each mechanophore type will be explored. This information will be useful in guiding future designs of mechanophores, particularly those capable of releasing small molecule agents without incurring bond scission within the polymer main chains. The PI also seeks to develop materials capable of amplifying the response of a single, site-specific mechanochemical event into a cascade release of multiple small molecules. This will be achieved through the development of mechanophores capable of triggering head-to-tail depolymerization of self-immolative polymers. The outcomes of this research will be a deeper understanding of how specific activation mechanisms influence mechanophore efficiency, and the ability to amplify the output from single mechanophore activation. These research efforts will be directly integrated with an education plan for collaboration between high school science students and university researchers. Specifically, the PI will work with members of a local area high school to design a science curriculum centered on problem-based learning. Members of the PI's research team will help design and implement coursework and lab experiences that mimic the experiences of undergraduate and graduate researchers in chemistry.