(141g) Mechanism of Evaporation-Driven Growth of Metal-Organic Framework Thin Films

Metal-Organic Framework (MOF) thin films offer exceptional properties for diverse applications, yet their controlled synthesis remains a challenge. Evaporative crystallization leverages known thin-film growth physics, such as solvent drying and solute concentration gradients, to produce MOF films. However, knowledge gaps persist regarding the unique nucleation and growth mechanisms of these highly porous, crystalline materials under dynamic evaporative conditions. This study bridges these gaps through a powerful combination of precise solvent-sheared growth, in-situ wide-angle X-ray scattering (WAXS), and a novel microkinetic model. The WAXS measurements directly reveal real-time structural evolution, while our microkinetic model elucidates the fundamental mechanisms controlling framework assembly, from initial nucleation to final film properties. This approach identifies key parameters that control MOF thin-film growth, such as evaporation driven growth and termination driven by change in linker order, extending beyond existing models. Importantly, this study demonstrates the applicability of this new modeling framework to predict and optimize film properties across a range of potential MOF systems. This enhanced understanding empowers the rational design of functional MOF thin films, significantly advancing advancements in fields including separation technologies, catalysis, and sensing.