CAREER: Chemomechanics of 2D Transition Metal Materials

This Faculty Early Career Development (CAREER) project aims to reveal the fundamental coupling between the chemical reactivity and mechanics of two-dimensional (2D) transition metal materials. Being mostly surfaces, the high chemical reactivity of 2D transition metal materials makes them ideal for chemical and biological sensing for environmental and health condition monitoring. However, the same chemically active nature makes 2D transition metal materials vulnerable to attacks from the complex environmental conditions. Understanding the coupled chemo-mechanical coupling is critical in synthesis, design, and fabrication of resilient 2D transition metal material devices. In this project, advanced experimental methods will be used to understand the underlying mechanisms that give rise to this coupling, which will advance the performance of these materials and accelerate their integration in industrial applications. The education and outreach plan will be centered on equipping students with the state of art knowledge and skills in 2D materials. The plan includes participation of underrepresented students from the rural Ozark school districts in the summer research program and recruitment of undergraduate STEM students to join the research team in reaching out to local medical communities. Recently developed prototype devices such as 2D antibacterial filters and MXene field effect transistors will be showcased in the summer camp program and outreach science tours. The PI’s research team will achieve investigate chemo-mechanical coupling in 2D materials from three perspectives: (1) identifying the role of mechanical strain in affecting the chemical reactivity, (2) investigating the chemical reaction induced adhesion degradation, and (3) discovering the fracture behavior of chemically reacted 2D transition metal materials. MoS2 (typical 2D transition metal dichalcogenides, or TMDs) and Ti3C2O (typical 2D transition metal carbides, or MXenes) will be used as the template materials and oxidation will serve as the model chemical reaction. The PI will characterize the chemo-mechanical coupling mechanisms utilizing the newly developed experimental approaches including, (1) mechanically strained oxidation, (2) atomic force microscope (AFM) adhesion characterization with functionalized probe, and (3) in-situ scanning electron microscope (SEM) and transmission electron microscope (TEM) fracture experiments in combination with chemical reaction characterizations. Atomistic modeling and continuum mechanics-based theories will also be established to rationalize these characterized chemo-mechanical coupling mechanisms. 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.