Metal-organic frameworks (MOFs) are porous, high surface area materials that consist of metal-cluster nodes connected by organic linkers to form highly ordered structures with various pore geometries and chemical properties. Due to their unique and tunable structure, MOFs have shown substantial promise in a broad range of applications, including chemical sensing, gas adsorption and separation, and catalysis. To investigate the intrinsic properties of MOFs for their sensing performance, single crystals are ideal platforms that mitigate the impact of defects, impurities, and grain boundaries that exist in polycrystalline sensing films. MOF crystals are typically grown by combining precursor solutions under vigorous mixing; therefore, the turbulence improves reaction efficiency. Under normal gravitational conditions (1 g) on the Earth’s surface, this process is affected by buoyancy-driven convection, which leads to uneven growth rates and sedimentation of crystallites in solution, reducing the ultimate size of the crystals produced. When growing MOF crystals in microgravity, the buoyancy-driven convection which dominates growth conditions at 1 g is no longer present, and the same growth systems become capable of producing much larger (up to millimeter scale) crystals. Growing crystals in conditions that minimize convective transport also generally exhibit significantly reduced defect densities, meaning that these larger crystals may have improved properties as well. In this project, we aim to develop an International Space Station (ISS)-compatible synthesis of MOF crystals which will then be implemented using the ADvanced Space Experiment Processor (ADSEP) facility on ISS. The MOF crystals grown under microgravity conditions will then be compared to the crystals grown on Earth and their properties for chemical sensing will be explored.
Project is currently funded by: Federal