Grant: Discovery Grants Program - Individual

Recent years have witnessed tremendous efforts aimed at developing functional molecular and materials systems. In many cases, these systems are designed to undergo chemical reactions that perform mechanical work in response to external stimuli such as light, heat, or an electrical current. Examples include molecular shuttles and motors, walking plastics, and microscopic actuators. An alternative, less-explored avenue involves the opposite process in which chemical reactions are induced by performing mechanical work on the system by subjecting it to external stresses. The development of stress-activated systems may have significant benefits given the inherently large stresses present in many real-world systems. For example, it may be possible to develop functional lubricants that respond and adapt to the changing stresses in sliding contacts to optimally control friction and wear, molecular stress sensors that detect damage in infrastructure, and even drug delivery systems that are activated in response to the stresses experienced upon adsorption at specific cellular sites. To develop stress-activated functional systems, it is necessary to understand the relationship between applied stress and chemical reactions. The proposed research will use quantum chemical simulations for this purpose and follow three integrated avenues. First, new methods will be developed to permit simulations of realistic model systems subjected to stresses and strains. Second, these techniques will be used along with conventional simulation methods to study how molecular systems respond to external stresses. The simulations will focus on tribochemistry, which involves reactions occurring in lubricating contacts, and mechanochemistry, which involves the activation of reactions by stretching molecular systems. Third, the results will be used to formulate predictive models relating molecular-level behaviour to macroscopic properties to guide the rational development of stress-activated functional systems. The work itself draws on chemistry, physics, materials science, applied mathematics, computer science, and engineering, which will provide five graduate students and two postdoctoral fellows with valuable interdisciplinary experience.