MOFs at Interfaces: Opportunities in Membrane Separation and Devices
26th September, Thursday, 12:00‐1:00 pm, ChE Seminar hall
Recently, new opportunities to deploy metal organic frameworks in membrane separation and devices have rapidly emerged. Overcoming some of the challenges of synthesizing thin, coherent films as well as integration with polymeric substrates have meant that the unique properties of MOFs can now be exploited in form factors which are viable for potential industrial applications as well as sensing devices. The high compatability of nanosize MOF particles in polymer matrix allows fabrication of ultrathin mixed matrix coatings on porous supports which provide mechanical stability. Applications range from enhancing gas separation with functionalized UiO-66 to pervaporation desalination where defect engineered MOFs can enhance water transport for dewatering of high salinity brines. We also explored several approaches in facilitating pure MOF film formation on polymeric membrane substrates. First, functionalization of polymer substrates with sol-gel coatings allows more facile attachment of ligands to promote MOF nucleation as well as providing a rigid exo-skeleton for thin MOF layers to grow. This has resulted in submicron ZIF-8 films to be readily grown for gas separation applications. Another approach is to use bioinspired polydopamine/polyethylenimine (PDA-PEI) coatings which can also nucleate thin ZIF-8 films. Step-wise SEM imaging and time resolved synchrotron X-ray scattering techniques were used to investigate the ZIF-8 growth process on two types functionalized surfaces to probe the differences in the quality and structure of the films. The ease of MOF deposition with the PDA-PEI approach in itself opens up new opportunities in spatial patterning MOFs on surfaces to exploit both the optical properties of thin MOF films as well as biomedical devices with spatially imprinted MOF-enzyme complexes for sensing.