Continuous, One-pot Synthesis and Post-Synthetic Modification of NanoMOFs Using Droplet Nanoreactors

Abstract

Metal-organic frameworks (MOFs); also known as porous coordination polymers (PCP) are a class of porous crystalline materials constructed by connecting metal clusters via organic linkers. The possibility of functionalization leads to virtually infinite MOF designs using generic modular methods. Functionalized MOFs can exhibit interesting physical and chemical properties including accelerated adsorption kinetics and catalysis. Although there are discrete methods to synthesize well-defined nanoscale MOFs, rapid and flexible methods are not available for continuous, one-pot synthesis and post-synthetic modification (functionalization) of MOFs. Here, we show a continuous, scalable nanodroplet-based microfluidic route that not only facilitates the synthesis of MOFs at a nanoscale, but also offers flexibility for direct functionalization with desired functional groups (e.g., -COCH3, fluorescein isothiocyanate; FITC). In addition, the presented route of continuous manufacturing of functionalized nanosized MOFs takes significantly less time compared to state-of-the-art batch methods currently available (1 hr vs. several days). We envisage our approach to be a breakthrough method for synthesizing complex functionalized nanomaterials (metal, metal oxides, quantum dots and MOFs) that are not accessible by direct batch processing and expand the range of a new class of functionalized MOF-based functional nanomaterials.

Recent advances in process engineering and upcoming applications of metal–organic frameworks

“…Microfluidic methods are optimal for fine-tuning the MOF crystal size and various morphologies and combinations, like core–shell, metal composited [133] , post-synthetic modification (PSM)-functionalized [134] , and hollow MOFs [135] . The reaction occurs only in the nanoliter droplets, where the high surface-to-volume ratio enhances the heat and mass transfer and reduces the reaction time.…”

Boosting CO2 adsorption and selectivity in metal–organic frameworks of MIL-96(Al) via second metal Ca coordination

“…24 DSM aims to enhance the textural characteristics and active functionalities of the parent MOFs by adding the second metal and other chemicals in one pot during the synthetic process. 25 However, DSM is very limited in preparation of M-MOFs because of the unfavourable existence of the central and second metal in the same reaction pot, which may result in unstable frameworks with weak topologies and functional groups. 26 To overcome this problem, suitable metals of similar ionic radii and coordination geometry are considered to maintain the integrity of the structures in M-MOFs during the DSM synthesis.…”

A Microfluidic Platform to design Multimodal PEG - crosslinked Hyaluronic Acid Nanoparticles (PEG-cHANPs) for diagnostic applications

“…In addition, when microfluidic platforms are used as microreactors, they provide improved space-time yields (product formed per reactor volume and time), producing faster reactions than bulk counterparts. Moreover, the degree of control over local environmental conditions is such to guarantee homogeneous products [33][34][35][36] .…”