CAREER: Elucidating the Synergistic Effects of Composition, Porosity and Structural Rigidity on Mechanics of Metallic Organic Frameworks

Arizona State University, Scottsdale AZ

Investigators

Abstract

This Faculty Early Career Development (CAREER) Award will support research to uncover the fundamental relationships between composition, porosity, atomic structure, and the mechanical behavior of glassy metallic organic frameworks (gMOFs). gMOFs are porous hybrid materials, often consisting of metallic ions, connected by organic linkers (ligands), to form a vast reinforced network. A major advantage of gMOFs is that they can be made in bulk, in diverse shapes, for a variety of applications. This award will promote the progress of science by focusing on the experimental understanding of the compression and shear behaviors of these absorbent materials, which is crucial for their use in industrial CO2 capture, separation, and storage applications. The techniques and testing developed herein are generic and will also increase the understanding of mechanical responses in materials similar in characteristics to gMOFs. This project will also provide training to students from high school through graduate college via research opportunities and innovative educational material. Special efforts will be made to recruit Native American students in STEM. The objective of this award is to understand the following phenomena in gMOFs: (1) the nature of inelastic dissipation processes, (2) the underlying distinct influences of structural order, composition, and density, and (3) the influence of energy relaxation on the ability to accommodate contact loads. The integrated experimental-computational approach will start with AFM-based indentation and scratch testing to quantify compression and shear responses at small scales. Second, the effects of different porosities will be determined by testing tectosilicate zeolites that contain similar pore sizes and pore size distributions compared to the gMOFs. Third, to relate the mechanical properties to the rigidity of the atomic structure, MD simulations coupled with topological constraint theory (TCT) will be performed. Finally, bulk mechanical behavior of the gMOFs will be experimentally characterized to correlate the influence of smaller scale inelastic dissipation mechanisms on macroscale elastic/strength properties and inelastic behaviors. 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.